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The Sweat-Louse, the Dirt-Mouse, and the Dong-Chong
A Study of Spontaneous Generation in Jewish Law

by Rabbi Nosson Slifkin

Do lice hatch from eggs, or do they grow from dust and sweat?

Are all mice born from other mice, or are some of them born from dirt?

Are lambs always born from sheep, or can they sometimes grow from vegetables? For most of history it has been widely accepted that animals can come into existence through spontaneous generation – that is to say, they are not born of other animals. In Jewish literature we find several mentions of such phenomena. Halachos pertaining to such creatures are ruled upon. Yet contemporary science rejects spontaneous generation as being a totally mistaken belief.

Recently, a Talmud scholar in Israel who became irreligious published a series of leaflets that highlighted problems and difficulties in Torah literature. The first of these dealt with the topic of spontaneous generation. The leaflet cited all of the Torah sources that accept this phenomenon, and none of those that reject it. Ostensibly, it merely presented the point that Chazal’s knowledge of science was no better than that of gentile scholars of their era. But the derisive style of writing, and the content of further leaflets, made other points: that Torah scholars throughout the generations have been gullible and naive, and in some cases foolish and intellectually dishonest.

Are his conclusions correct? Orthodox Jews believe that the views of Torah scholars through the ages must be treated with great respect. Furthermore, contrary to popular opinion, it is accepted that the further back in time one goes, the greater the stature of the scholars. The Sages of the Talmud were spiritual giants, whose greatness we cannot fathom. Yet this does not preclude a rational and reasonable discussion of conflicts between sages and scientists. This essay analyzes the topic of spontaneous generation in depth, including the implications for those who believed in the phenomenon, and the ramifications of the Torah laws that deal with it.

I. The Sweat-Louse

The Talmud states that lice spontaneously generate:

Rabbi Eliezer said: One who kills a louse on Shabbos is like one who kills a camel on Shabbos... the Rabbanan only disagree with Rabbi Eliezer in the case of lice, which do not reproduce... Abaye said: And do lice not reproduce? Surely it was said, “God sits and sustains from the eggs of lice (betzei kinnim) until the horns of re-eimim”? – That refers to a creature which is called betzei kinnim.

(Shabbos 107b)

Some variant texts state that lice “do not reproduce by way of male and female.” Certain species of lice reproduce parthenogenically, meaning that females reproduce by themselves. No male louse has ever been found (although there are some women who disagree with this!). Thus, it is proposed that the Talmud is not stating that lice do not come from eggs, only that these eggs do not come from the conventional system of males and females. However, this resolution is problematic. The lice that are found on humans do not reproduce in this way, but rather through males and females. Additionally, if the Talmud was speaking about females laying eggs, it would have no difficulty with statement about God sustaining the eggs of lice. Furthermore, none of the classical commentaries on the Talmud understood it in that way. Tosafos (to Shabbos 12a) states that the type of louse known as the rocheshes is generated from human sweat. The Ran states that lice are generated from dust.

There are two issues that must be dealt with:

1) Is the statement of the Gemara, that lice do not reproduce via eggs, true?

2) If it is not true, what are the ramifications for the halachah and for the stature of the Sages?

Is it True?

With regard to the first question, contemporary knowledge of the natural world tells us that it is not true. All animals are born from other animals. In ancient times, people did not realize this, because they had less of an understanding of the natural world, and the eggs of certain insects are too small to be seen with the naked eye. They therefore believed that insects emerge from sweat and dirt.

A dissenting view is that of Professor Herman Branover, who writes:

Perhaps this sounds trivial, but it is an elementary principle that the only type of affirmative statement that can be made on the basis of empirical knowledge is the confirmation of the existence of an object or the possibility of a phenomenon. Therefore, for example, the “scientific” argument denying the possibility of certain types of insect reproducing through spontaneous generation – as acknowledged in the Torah and incorporated in Hilchos Shabbat – is meaningless. Methodologically, it is impossible to provide experimental evidence proving the impossibility of spontaneous generation. And indeed, modern adherents of the theory of Evolution clearly accept the possibility of spontaneous generation. The adequate balanced statement of the “Torah and Science” writer or lecturer on this subject should therefore be: “Torah acknowledges the possibility of spontaneous generation in some species, a phenomenon not yet observed by biological experimentation.”

(“Torah and Science: Basic Principles,” Encounter, p. 239)

There are several objections to be raised on this paragraph, such as that adherents of evolution do not accept spontaneous generation. However, let us address the main point, that we can only prove something but can never disprove the existence of something. While it is technically true to say that we can never categorically disprove the existence of something, there are nevertheless many cases where we are absolutely confident that certain things do not exist.

Let us consider, for example, vampires – in the sense of people who change into bats. We cannot conclusively prove that they do not exist. There have been, throughout history, many people who have firmly believed in such things. Yet we are utterly certain that they do not exist, for three reasons. First, all our knowledge of the world tells us that it is physically impossible for a person to transform into a bat. Second, we have good reason to believe that the vampire legend is based on kernels of true facts that were subsequently distorted, such as the existence of vampire bats that suck blood, and the existence of certain people with bizarre habits. Third, if vampires did exist, we would expect to find evidence of them.

Putting these three reasons together tells us that it is overwhelmingly more likely that the vampire legend is based on mistaken information rather than on an actual phenomenon. Thus, even though we cannot actually prove that vampires do not exist, we still do not believe that they do. Similarly, we would firmly state that fairies, leprechauns, and fire-breathing dragons do not exist, even though we cannot prove this. They are biologically improbable, and there is good reason to state that accounts of them are based on mistakes or tall stories; and if they did exist, why has no evidence of them been discovered?

If we turn to spontaneous generation, the same is true. All of our experience tells us that everything happens with a prior cause – with the possible exception of the beginning of the universe itself (to which we attribute a spiritual cause but no physical cause). In all the studies that have been made of the world, in all the video footage that has been shot, nobody has ever seen an animal pop into existence except where being born from another creature. Lice are born from other lice; they are not spontaneously generated from sweat or dirt.

Why Would People Believe It?

Now let us explore if there is reason to believe that accounts of spontaneous generation are based on mistakes rather than genuine phenomena. But first, we must respond to the suggestion that the Sages were not speaking about the lice with which we are familiar, but instead about a particular species of lice that is currently unknown to us (or extinct) and does indeed spontaneously generate. This is extremely unreasonable. Until the late 17th century, the entire world believed that lice (as well as many other creatures) are spontaneously generated. It is highly unreasonable to state that when the Sages spoke of spontaneously generating lice, they were speaking not of the lice that the entire world mistakenly believed to be spontaneously generated, but instead of a different species that is currently unknown. It would have been a ruling that would have been totally misunderstood by everyone!

There is good reason to believe that the statement of the Sages is based on flawed information. As we noted, the entire world used to believe that spontaneous generation occurs with a wide range of creatures. An excellent discussion of this topic is to be found in Jan Bondeson’s fascinating work, The Feejee Mermaid and Other Essays in Natural and Unnatural History, (New York: Cornell University Press 1999), from which the following sources are taken.

Aristotle wrote that certain lower animals “are not produced from animals at all, but arise spontaneously: some are produced out of the dew which falls on foliage... others are produced in putrefying mud and dung, others in wood, green or dry, others in residues, whether voided residues or residues still within the living animal.” Eels and fishes come from the foam of the sea, insects from sand whirled into air by wind, and wasps from cadavers of dead horses.

One Sir Thomas Browne did not disagree with the concept of spontaneous generation, but he doubted whether this could also include mice. Alexander Ross, an Aristotelian, wrote in response:

He doubts whether mice can be formed of putrefaction! So may he doubt whether in cheese and timber worms are generated; or if butterflies, locusts, grass hoppers, sel-fish, snails, eels and such are procreated of putrefied matter... To doubt this is to question Reason, Sense, and Experience...

The Egyptians believed that insects, frogs, mice, crocodiles and other strange creatures could be generated in the fertile humus left by the flooding of the Nile. The Roman poet Virgil in his Georgics writes that bees are formed from the flesh of oxen. Arab naturalists in the Middle Ages accepted Aristotle’s teachings, and suggested that even humans could arise from putrefying matter. The influential Italian mathematician, naturalist and physician Girolamo Carano included a large section in his de Subtilitate on spontaneous generation, in which he explained that not only ants, flies, fish, and crayfish, but even mice, hares, and gazelles were regularly born this way. When theologian Wolfgang Franzius published his Historia Animalium Sacra in 1612, claiming that no animal could be born without parents, he was ridiculed as being completely ignorant of modern biology.

Where did these ideas come from? They are likely to be simply due to the fact that it did not occur to anyone to think differently. Meat left out to rot would soon swarm with maggots. Nobody had watched flies lay eggs, and many of these eggs would either not have been visible to the naked eye, or not recognizable as eggs. It seemed obvious that the meat itself was generating the insects. There was no systemized study of science in those days to prove otherwise.

There is an interesting phenomenon that may, at least in part, have contributed towards the myth of spontaneous generation. The burrowing frog lives in arid regions and deserts. At the start of a long dry spell, when the pools from the last rainstorms are in the last stages of evaporation, the frog buries itself up to twelve inches deep in the mud. There it settles into a state of suspended animation, with its breathing and heartbeat slowing to a rate just sufficient to keep it alive. After about two weeks, the outer layers of the frog’s skin detach and meld together into a membrane that is fully waterproof apart from two tiny tubes to the frog’s nostrils. The frog can survive in this state amidst desert drought for many years. Then, when the rainfall finally comes and turns the sand into mud, the frog breaks out if its bag and emerges upon the surface, appearing to have grown from the mud.

Figure 1: A burrowing frog emerging from its sac

For whatever the reasons, spontaneous generation was widely accepted well into the seventeenth century. A change occurred in 1636 when physician and philosopher Daniel Sennert published his Hypomnemata Physica, claiming that new life could generate only from once living matter – flies could be engendered from meat, but not from dirt. Yet philosopher Rene Descartes disagreed. It was only towards the end of the seventeenth century that experiments by Francesco Redi and Louis Pasteur surprised the world by proving that substances that were protected from the air did not produce insects. The myth of spontaneous generation was finally laid to rest.

The Implications About The Sages

Many people are uncomfortable with this topic, because of the ramifications for the Talmud. One feared ramification is that it demonstrates the Sages to have been gullible or foolish. Another is that it means that the law about killing lice on Shabbos should be changed – and once one starts changing laws, who knows where that will end?

The response to the first concern is that the belief of the Sages in spontaneous generation does not mean that they were at all gullible or foolish. Gullibility has to be measured against the knowledge that one already possesses.

For example, if a newspaper were to report that a new species of monkey, two feet in height, with Mohawk-style hair, no thumbs, a bright red face, and a long nose that droops over its mouth, has been discovered in the rainforests of Costa Rica, the average person might be skeptical. However, a zoologist, who possesses a thorough knowledge of the animal kingdom, would not be so skeptical. For there actually are species of monkeys with Mohawk-style hair, red faces, no thumbs, and a droopy nose. If, however, the newspaper reported that a new species of monkey was discovered with dark green fur, there would be no particular reason for the average person not to believe it. But the zoologist would have reason to be skeptical, for not one of the 5,000 known species of mammals is green.

In ancient times, based on the information available, there was no particular reason not to believe in spontaneous generation. As we have seen, there were kernels of truth in observations of spontaneous generation. Nobody had ever performed experiments to disprove it. There was no systemized knowledge of the natural world. It was perfectly reasonable to believe in spontaneous generation, and we should not scorn the people of that era for being gullible, any more than we would criticize the average person for believing in a turquoise monkey.

In any case, it should be noted that there seem to be far fewer citations of mythical creatures in Jewish texts than in other texts. Perek Shirah, for example, the classical Jewish work of natural history, lists only known animals, while the Christian bestiaries, which were moralizing fables, featured a host of mythical creatures.

Sages and Scientists

Rambam, in discussing scientific statements made by Chazal, gives us an important principle:

Do not ask of me to reconcile everything that they (Chazal) stated from science with the actual reality, for the science of those days was deficient, and they did not speak out of traditions from the prophets regarding these matters...

(Guide for the Perplexed, 3:14)

Following in his father’s footsteps, Rabbeinu Avraham ben HaRambam states:

...The great superiority of the sages of the Talmud, and their expertise in their explanations of the Torah and its details, and the truth of their sayings in the explanation of its general principles and details, nevertheless does not obligate us to defend them and uphold their views in all of their sayings, in medicine, and in scientific knowledge...

(Dissertation on Derashos Chazal)

Rabbi Samson Raphael Hirsch (d. 1888) writes as follows:

In my opinion, the first principle that every student of Chazal’s statements must keep before his eyes is the following: Chazal were the sages of God’s law – the receivers, transmitters and teachers of His toros, His mitzvos, and His interpersonal laws. They did not especially master the natural sciences, geometry, astronomy, or medicine – except insofar as they needed them for knowing, observing and fulfilling the Torah. We do not find that this knowledge was transmitted to them from Sinai.

...We find that Chazal themselves considered the wisdom of the gentile scholars equal to their own in the natural sciences. To determine who was right in areas where the gentile sages disagreed with their own knowledge, they did not rely on their tradition but on reason. Moreover they even respected the opinion of the gentile scholars, admitting when the opinion of the latter seemed more correct than their own.

(Trusting the Torah’s Sages, a letter written in 1876 to Rabbi Pinchas M.E. Wechsler, published in 1976 in the Jerusalem journal Hama’yan, Chapter 4)

Rabbi Hirsch cites as proof the following Gemara:

The Jewish sages said, “By the day the sun passes beneath the firmament and at night above it.” The sages of the nations maintained, “By day beneath the firmament and at night beneath the ground.” Rebbi said, “Their opinion seems more correct than ours.”

(Pesachim 94b)

The topic of Chazal’s knowledge of science is a complex one that cannot be adequately dealt with in this forum. An excellent work on the subject is Hishtanus HaTevi’im by Rabbi Nuria Guttal. There are some views which state that Chazal did indeed possess a superior or perfect knowledge of science, such as that of Rabbeinu Tam, the Rema, the Chidah, and the Aruch HaShulchan. Yet, as shown here, there are certainly authoritative views, based on the straightforward understanding of the statement of Rebbi himself, which do not consider that their knowledge of science was any different than anyone else of that era. With the case of lice, recent scholars do understand that Chazal were mistaken in explaining that they spontaneously generate; it is only the legal ramifications of this that are subject to dispute, as we shall now explore.

There is a suggestion, which is commonly heard, that follows the approach of saying that the Sages of the Talmud could not have made a mistake about natural phenomena. According to this approach, the Sages were not speaking about the lice with which we are familiar and hatch from miniscule eggs, but instead about a particular species of lice that is currently unknown to us (or extinct ) and does indeed spontaneously generate. This is extremely unreasonable. As we have seen, until the late 17th century, the entire world believed that lice (as well as many other creatures) are spontaneously generated. It is highly unreasonable to state that when the Sages spoke of spontaneously generating lice, they were speaking not of the lice that the entire world mistakenly believed to be spontaneously generated, but instead of a different species that is currently unknown.

Furthermore, it would have been a ruling that would have been totally misunderstood, and misapplied, by almost everyone! Suppose one posits that the sages of the Talmud possessed impeccable knowledge of nature and could only have been speaking about lice that really do spontaneously generate. But they must also surely have known that many simple people of their generation, and of subsequent generations, believed that ordinary lice are also born through spontaneous generation, and would transgress Shabbos by killing them!

And consider how, throughout the ages, the commentaries on the Talmud spoke of the permissibility of killing lice on Shabbos due to their spontaneous generation. The recent authorities were certainly speaking of the same lice with which we are familiar. If we posit that the Talmud itself was speaking only of a particular louse that really does spontaneously generate, then at which point did this ruling become entirely misunderstood and misapplied to ordinary lice?

For all these reasons, it is extraordinarily unreasonable to posit that the sages were not speaking of the ordinary lice with which we have been familiar for generations, but instead of an unknown species. We must accept that they were speaking of the same lice that Rambam, the Shulchan Aruch and Mishnah Berurah understood them to be speaking of – the lice which we all know.

Legal Ramifications

We have established that lice are not born via spontaneous generation, and the Sages were mistaken in stating that such is the case. The question now is what to do about the ruling that one may kill lice on Shabbos. This problem was first addressed by Rabbi Yitzchok Lampronti (d. 1756), author of the Talmudic encyclopedia Pachad Yitzchak, and mentor of the renowned Rabbi Moshe Chaim Luzzatto. He cites an opinion on this matter from Rabbi Yehudah Brill (d. 1722) of Italy:

“...There is no need for the believer to seek proofs and arguments from other places, even though they are many and powerful, for the received tradition of our rabbis suffices, for they entrenched and founded the complete judgment and law on the foundations of the matter. ...We are not to depart from that which has been ruled in our Talmud, even if all the spirit of human investigation in the world were to blow our way, for the spirit of G-d speaks within us. The knowledge of the researcher is lacking, and his intellect does not reach the depth of the wisdom of nature... the wise men of the nations of the world do not know nor understand nature, other than the superficial matters that are visible to the eye, and not their inner essence, as those who have received the traditions of the acts of Creation have grasped... And if so, the law is true, established, and correct, and existing in its place, and it is not to be changed at all...”

Rabbi Brill states that the law still stands – apparently because there are hidden reasons for it that elude us, rather than because Chazal are actually correct regarding spontaneous generation. But Rabbi Lampronti himself tentatively disagrees:

Were I not afraid, I would say that in our times, when the experts in reproduction have studied, watched, discovered and written that all animals, of whatever type, come from eggs, and they have proved all this with clear proofs, therefore someone who cares about his soul will distance himself from them and will not kill neither parosh-louse nor kinah-louse, and will not enter into a possible liability for a sin-offering. With this matter, I would say that if the sages of Israel were to hear the proofs of the nations of the world, they would retract to accept their words, just as with the matter of the spheres and constellations. ...Surely we are here to be stringent, not lenient... and the sages of Israel who retracted to agree with the wise men of the nations of the world in the matter of the fixed nature of the constellations and the revolution of the spheres pointed with a finger to the fact that not everything stated in the Gemara is from a received tradition. Rather, the sages of Israel also sometimes spoke from their wisdom, and from human investigation, not from received tradition; otherwise, why would they have agreed to the other position – they should have stuck to their received tradition and not retracted in the face of all the proofs of the nations of the world.

(Pachad Yitzchak, erech Tzeidah Asurah)

In contrast to this is the view of Rabbi Eliyahu Dessler. In a footnote to Michtav Me-Eliyahu, Rabbi Aryeh Carmell, one of Rabbi Dessler’s foremost students, writes as follows:

I have seen fit to note here that which I heard explicitly from Rav Dessler, zt”l, when he was asked about certain laws for which the reasons that have been given for them are inconsistent with the reality determined by scientists of later generations, and they are now in the category of that which the Gemara asks in many places, “But surely we see that it is not so!”

Three examples were considered:

- It is ruled that there is derusah with a cat and not with a dog, and the Gemara gives the reason that a cat exudes poison from its claws (Chullin 53a).

- It is ruled that we may only knead matzos with water that has been in our possession overnight, and the reason, according to several Rishonim, is that at night the sun passes beneath the Earth and heats up the springs (Pesachim 94b).

- It is ruled that one may kill a louse on Shabbos because the louse does not reproduce by way of cohabitation (but spontaneously generates) (Shabbos 107b).

Rav Dessler said that with these and similar cases the law is never changed, even though the reason is not initially understandable to us. Rather, we must firmly grasp the law with both hands, whether for stringent or lenient ramifications.

(This is in contrast to the opinion of R’ Y. Lampronti, zt”l, in Pachad Yitzchak, Section: Tzaidah Asurah, who wishes to be stringent and forbid killing a louse on Shabbos, since in our time it has been established beyond a shadow of doubt that lice reproduce through males and females like all creatures; see his discussion there.)

The reason for this, explained Rav Dessler, is that Chazal knew the law as a tradition from earlier generations. They also knew from experience that, for example, maulings by cats are more likely to result in deaths than maulings by dogs, and that water drawn from springs in the mornings are warmer. But with regard to scientific explanations, it is not that the explanation mandates the law, but rather the opposite: that the law mandates an explanation. The reason given in the Gemara is not the sole possible reason. And if, on occasion, they gave an explanation according to the scientific knowledge of their day, we are obligated to search for other explanations which establish the law on its basis according to the scientific knowledge of our day.

Thus I heard from Rav Dessler, zt”l. According to this principle, we can perhaps say, for example, as follows:

The poison of which Chazal spoke is poisonous matter which accumulates under a cat’s claws from rotting remnants of flesh that remain from earlier prey. Note that a cat’s claws differ to a dog’s claws, in that a cat’s claws are composed of two sections, and when a cat swipes in order to kill it extends its claws to penetrate into the flesh, and when it withdraws them, some of the poisonous matter remains, to cause damage. All of the particulars of this law are thereby explained, for we find there: “Derusah is only with the front legs, to exclude the hind legs; derusah is only with the claws, to exclude the teeth; derusah is only when done intentionally etc.”; and it is only when done in anger (Rashi, Chullin 52b, s.v. aval). All of this is explained according to that which we have written.

Similarly with water - we can easily explain why our water is colder than that which is drawn from the well in the morning. During the night, the air cools rapidly, and therefore the water that is in our vessels also cools. But the ground cools at a slower rate, because of the heat that has accumulated in it during the day (and is insulated). Therefore, in the morning, the water that is drawn from wells, which has been in the ground, is likely to be warmer than water which has been standing in the night air.

With regard to the matter of the louse, the explanation is a little more difficult. However, it is a known principle that the halachah only considers that which can be detected by the senses. According to this, perhaps we can say that since the egg of a louse is extremely small, so much so that at the time of the giving of the Torah it could not be detected at all, the halachah does not consider it at all, and the louse is rated as though it was born from the material which it grows in and consumes, and thus it is rated as a lower degree of life-form, for which there is no prohibition of taking a life. We can explain similarly for insects that grow in fruit. The egg that the parent lays in the fruit, from which the insect hatches, cannot be seen at all and is considered as though it does not exist. Therefore, these insects are considered by the halachah as though they were born from the fruit itself, in which they grow, and they are permitted to eat, just like the fruit, as long as they did not crawl on the ground, since for this there is a special clause (Sifra, end of parashas Shemini).

All such matters can be explained in similar ways. And even if we do not find an appropriate reason, we shall believe with perfect faithfulness that the law is a true law, and we shall look to Hashem to illuminate our eyes to find a fitting explanation.

(vol. IV, p. 355)

It is fascinating to contrast Rav Dessler’s approach with that of the cited Rav Lampronti. Dealing with laws of Shabbos, which are extremely stringent, Rav Dessler does not even see any cause to prohibit killing lice just to be “on the safe side.” (Note that Rav Lampronti himself does not say that the halachah is clearly to be changed; he just wishes to cover all possibilities.) Rav Dessler’s conviction in the ultimate truth of the halachah dictates that there is simply no need to take this precaution (and there is perhaps even an element of heresy involved in trying to be “on the safe side”).

Some claim that the explanations described by Rabbi Carmell was actually the intent of the Gemara; Chazal actually meant only that the eggs of lice are halachically insignificant, not that they don’t exist. But aside from this being an unreasonable explanation of the words of the Gemara, and lacking any proof, there is a straightforward refutation of this argument. Why would Chazal then reject the simple meaning of the statements that speak about the eggs of lice? Let them simply state that although lice do hatch from eggs, these are too small to be halachically significant! It is clear that they did not consider this possibility. Neither Rav Lampronti nor Rav Dessler stated that Chazal were referring to a type of louse that actually does spontaneously generate.

Strangely, the Mishnah Berurah (316:9:38) does state that lice are born through spontaneous generation. It is unclear whether the Chafetz Chaim was simply unaware of the advances of science, if he disagreed with them, if he considered them irrelevant to the halachic discussion, or if he had reasons not to involve himself in this topic.

In summary: the statement of the Gemara that lice spontaneously generate is mistaken. This has no derogatory explanations whatsoever for the stature of the Sages (unless one formerly considered them to be omniscient, a distinction usually reserved for God alone). The halachic implications, however, are disputed.

II. Vegetable Humanoids and Lambs

Another intriguing case of an animal that is not born of parents is found in the Mishnah. There is a discussion of the laws concerning a peculiar creature known as the adnei ha-sadeh, literally “master of the field”:

Adnei ha-sadeh is rated as an animal. Rabbi Yosi says: It causes spiritual impurity (when dead) in a building like a human being.

(Kilayim 8:5)

What is the adnei ha-sadeh? Rabbi Ovadia MiBartenura explains:

Adnei ha-sadeh – A large animal of the fields, and a sort of large cord extends from the ground where it grows. It is [also] called yedua, and it is the yidoni that is mentioned in the Torah. It is joined at the navel to the cord that emerges from the ground, and it is formed like a human being, in its face, hands and feet, and no creature may approach it, for it kills and mauls anything that approaches it. When they want to capture it, they shoot arrows at the cord until it breaks, and it cries out in a bitter voice, and dies instantly. Iyov referred to it when he said, “For Your covenant is with the avnei ha-sadeh” (in some texts, the adnei ha-sadeh is called the avnei ha-sadah) (Iyov 5:23).

The yidoni to which he refers is the medium of sorcery prohibited in the Torah:

Do not turn to the ovos and the yidonim; do not seek to contaminate yourselves with them; I am Hashem your God.

(Leviticus 31:19)

Rashi explains that the yidoni practice refers to a person taking the bone of a creature called yedua, placing it in his mouth, and causing it to speak.

The Talmud also discusses such a creature:

Adnei ha-sadeh, the yaysi-araki, is the mountain-man, and it lives via its navel. If its navel is detached, it cannot live.

(Talmud Yerushalmi, Kilayim 8:4)

It should be noted that this explanation of the adnei ha-sadeh is not the only explanation. Rabbi Yisrael Lipschutz (d. 1860), in his Tiferes Yisrael commentary, explains the adnei ha-sadeh to refer to a different animal entirely:

It seems to me that it means the “wildman” which is called “orangutang.” This is a type of large ape, genuinely similar to a person in form and build, except that its arms are long, reaching to its knees. It can be taught to chop wood, to draw water, and also to wear clothes, just like a human being; and also to sit at a table and eat with a knife, fork and spoon. In our times, it is only found in the great jungles of Africa; however, it appears that it may formerly have been found also in the vicinity of the Land of Israel, in the mountains of Lebanon, where even in our day there are great forests, of the “cedars of Lebanon” fame; and therefore it was called “the mountain-man.”

(Yachin ad loc.)

Nevertheless, the Tiferes Yisrael himself cites the alternate view. He defends the general criticism of it, but himself raises questions as to its biological viability:

Our sages explained that there is an animal that is shaped like a human being and is attached to the ground by a cord that emerges from its navel. It is extremely dangerous (see Ma’aseh Tuviah), and when the cord is severed, it dies instantly. Now, one should actually not be surprised that this is not mentioned in books of natural history; for likewise, we have found in the depths of the earth the bones of many creatures whose memory has been lost, such as the mammoth and similar creatures; perhaps this is also due to their great danger, living in the prehistoric forests of the land. And one should also not be surprised at how a living thing can grow from the ground. For we find a similar example with the rodent that grows from the ground; see that which we wrote, with the help of Heaven, in our commentary there. But there is reason to wonder how it could derive its sustenance with eating and drinking. Surely there is no creature that can exist without eating. It serves to fulfill, via the eating, that which is ground from the elements of which the body is composed, which are being ground up at every moment. Only through this can the deficits be filled. And it is a stretch to say that it takes its sustenance from the sucking of its navel from the ground. For the Holy One did not create anything in this world for nothing, and if so, why would it need a mouth, and eyes, and intestines? Even though the butterfly lives without eating, for it was created without a mouth, but the truth is that it is not long-lived, and only lives for a day; after it has mated, and the female has laid eggs, they both die. If we were relying on the Talmud Yerushalmi saying that it lives via its navel, then perhaps such would be the truth; but there is no mention of a cord that is attached to the ground.

(Boaz ad loc.)

The Tiferes Yisrael’s position is therefore that one can certainly challenge the biological statements of Rishonim. However, those statements of the Talmud must be treated with greater respect. He firmly respects the statement concerning the mouse that grows from the ground, which we shall soon discuss, and also states that were the Talmud to speak of the existence of the cord, “perhaps such would be the truth.”

The yidoni legend may also have an alternate version. The botanist Claude Duret, in his 1605 work Histoire Admirable des Plantes, writes that he “remembers having read” a text of the Talmud Yerushalmi which refer to the yidoni as being a lamb that grows from the ground rather than a humanoid. Various other secular works also speak of an ancient Hebrew legend in which the creature is shaped like a lamb, not a humanoid. The 1705 work Ma’aseh Tuviah (4:10) to which Rabbi Lipschutz referred above cites both the description of a humanoid and a contemporary account of a it taking the shape of a lamb, and concludes that the lamb account is more likely to be true that the humanoid account.

Figure 2: A vegetable lamb, from Claude Duret's Histoire Admirable des Plantes

The relevance of this alternate version is that the “vegetable lamb” was widely reported throughout the world in earlier centuries. The first accounts are in Chinese manuscripts, one dating before the year 429. In Europe, similar accounts later became widespread. The knight Sir John Mandeville wrote in 1356 that, when visiting Tartary, he had been served a lamb that grew on a stalk from the ground. Similar accounts of the “Vegetable Lamb of Tartary,” which was also known as the Boramez, became widely accepted. Imported skins of lambs that had supposedly grown from the ground fetched high prices.

It was only in the year 1698 that a complete specimen of a vegetable lamb, acquired from a Chinese collection of curiosities, reached European naturalists. Sir Hans Sloan of the Royal Society of London demonstrated this strange thing, which resembled a woolly branch with four legs. He was also able to determine what it really was: the large rootstock of a fern, ingeniously carved to look like a lamb. He was proved correct when the first of these unusual ferns was brought to Europe; they were named cibotium borametz, in honor of the Boramez legend.

It seems that these specimens were widely manufactured by Russians, Indians, and Chinese, who were skilful at fabricating the rootstocks into small animals. One beautiful example is on display at the Museum of Garden History in Lambeth, England; it really looks quite remarkable.

Figure 3: The vegetable lamb at the Museum of Garden History

As with the sweat-louse, we can confidently state that no creatures grow from plants. It would stand in contradiction to everything that we know about zoology (and botany), and there is a good explanation to account for the formerly prevalent belief in such things. Does all this mean that this discussion of Chazal is now worthless, and to be consigned to the history books? Far from it. Let us first explore our final case of claimed spontaneous generation, after which we shall discuss the benefit of these sections of Torah.

III. The Dirt-Mouse

Our final case of spontaneous generation is that of a certain rodent. The Mishnah discusses the laws concerning a mouse that is half formed of earth.

A mouse which is half flesh and half earth; if someone touches the flesh part, he is tamei; if he touches the earth part, he is tahor.

(Chullin 9:10)

This creature supposedly grows from the earth, and thus passes through a stage in which it is part earth and part mouse. It is also cited in the Talmud as a proof for the resurrection of the dead:

A certain sectarian said to Rabbi Ami: You say that the dead will live again - but they become dust, and can dust come alive? He replied... Go out to the field and see the rodent that one day is half flesh and half earth, and on the next day it has transformed into a creeping creature and has become entirely flesh.

(Sanhedrin 91a)

As with the lice, and the yidoni, we can confidently state that this creature does not actually exist. There is no biological explanation for such a phenomenon, and there is good reason to believe that it is based on mistaken observations. Rambam, in an interesting comment on this Mishnah, may also hint to a certain skepticism:

This is a well-known matter; there is no end to the number of people who have told me that they have seen it. This is despite the fact that the existence of such a creature is astonishing, and I do not know of any explanation for it.

(Perush HaMishnayos)

There are two ways of understanding Rambam. One could say that he is confidently supporting the existence of this creature. Alternatively, one could say that the fact of his acknowledging the existence of such a creature is not so important; as he states, he is basing his opinion on a large amount of eyewitness testimony. What is important to note is that Rambam sees fit to debate the authenticity of such a creature. He does not blithely go with the Mishnah. Rather, he was “astonished” that such a creature could exist, and sees it as necessary to cite eyewitnesses in order to allay doubts, not faith in the Sages of the Mishnah. This would be consistent with the position of Rambam cited earlier that he did not consider that the Sages possessed perfect scientific knowledge.

A fascinating addendum is written parenthetically by the Tosafos Yom Tov:

(It seems to me that this is a strong objection to those who believe in kadmus.)

(Tosafos Yom Tov ad loc.)

Kadmus> was a theory prevalent for much of history. It posited that there is no prior cause for physical existence; rather, the universe has always existed in the state that in which it exists today, and mice have always been descended from earlier mice. A creature that is born from inanimate matter refutes such a theory, and indicates that the universe can indeed pop into existence ex nihilo. The science of today does not subscribe to the theory of kadmus. The current understanding is that the universe inexplicably sprang into existence a long time ago. However, this does not prove that mice can also inexplicably spring into existence.

Rabbi Yisrael Lipschutz, in his commentary Tiferes Yisrael, defends the existence of this creature:

...I have heard heretics mocking regarding the creature that is discussed here and in Sanhedrin 91a, and denying it, saying that there is no such thing at all. Therefore, I have seen fit to mention here that which I found written in a Western European work compiled by a scholar renowned amongst the scholars of the world. His name is Link, and the book is titled Urwelt. In Volume I, page 327, he writes that such a creature was found in Egypt in the district of Thebes, and that rodent is called, in the Egyptian language, dipus jaculus; and in the language of Ashkenaz it is called springmaus. Its forequarters – its head, chest and hands – are perfectly formed; but its hindquarters are still embedded in the earth, until after several days when it fully changes to flesh. And I say, “How great are Your works, Hashem!”

(Boaz ad loc.)

However, Professor Sid Z. Leiman, in an article entitled R. Israel Lipshutz and the Mouse that is Half Flesh and Half Earth: A Note on Torah U-Madda in the Nineteenth Century (printed in Hazon Nahum, New York: Yeshivah University 1998), has demonstrated that Rabbi Lipshutz actually misunderstood Link.

Heinrich Friedrich Link (1767-1850) was a German botanist and Zoologist. The full title of the book cited by Rabbi Lipshutz is (in translation) “The Primeval World and Antiquity Elucidated by Natural History.” In discussing ancient Egypt, Link cites Diodorus Siculus, a first-century B.C.E. Greek historian, who reports that the Egyptians state that life first began in Egypt, and as proof of this, they note that mice are generated in vast numbers from the soil of their land. Diodorus himself concurs that this takes place:

Indeed, even in our day during the inundations of Egypt, the generation of forms of animal life can clearly be seen taking place in the pools which remain the longest; for, whenever the river has begun to recede and the sun has thoroughly dried the surface of the slime, living animal, they say, take shape, some of them fully formed, but some only half so and still actually united with the very earth.

Here is where Link himself adds a footnote to the account of Diodorus:

The Springmaus (Dipus Jaculus), which dwells in Upper Egypt and is characterized by very short forelegs, looks as though it is a creature that is not yet fully developed.

The animal being referred to is the jerboa. The jerboas are a family of tiny to large rodents that have long back legs for jumping and dig burrows in which they sleep. One of the three subfamilies is known as Dipodinae and it includes the genus Jaculus; this is the dipus jaculus mentioned by Link.

Figure 4: A jerboa

Professor Leiman points out that Rabbi Lipshutz appears to have made several mistakes in his citation of Link. Link is not stating that dipus jaculus grows from the ground. He merely states that its tiny forearms look like those of a creature that is incomplete. (Actually, the tiny forearms of the jerboa are perfectly suited to the jerboa’s lifestyle.) It is certain that Link himself, who lived in the nineteenth century, and was very familiar with the jerboa, did not believe that it or any other animal grows from the ground. Rather, he is saying that this creature may be the source of the Egyptian myth.

Rabbi Lipshutz, on the other hand, understood Link to be saying that dipus jaculus actually was the creature that the Egyptians spoke of. Hence, he mistakenly stated that dipus jaculus is an Egyptian, rather than Latin, name. Furthermore, he took Link to be attesting to this creature growing from the ground.

The approach of Rabbi Lipshutz, with its errors, is peculiar. This is especially so when we consider his very different approach with the adnei ha-sadeh; but we should not forget the context in which he was speaking here – to refute “the heretics.” Presumably he is referring to people who used such a claim to scorn the Torah in general; he states that they were “mocking,” and he therefore preferred to use the citation from Link rather than to search for a more rational explanation.

Yet not all people who deny the existence of such a creature are heretics; there are approaches that also suggest that the scientific data may be inaccurate, but which do so in a way that in no way belittles Chazal. We have already seen the approaches of Rabbi Lampronti and Rabbi Dessler regarding spontaneously generating insects; let us now explore the approach of Rabbi Samson Raphael Hirsch to this case in particular. He writes:

Imagine if a scholar such as Humboldt had lived in their times and had traveled to the ends of the world for his biological investigations. If upon his return he would report that in some distant land there is a humanoid creature growing from the ground or that he had found mice that had been generated from the soil and had in fact seen a mouse that was half earth and half flesh and his repost was accepted by the world as true, wouldn’t we expect Chazal to discuss the Torah aspects that apply to these instances? What laws of defilement and decontamination apply to these creatures? Or would we expect them to go on long journeys to find out whether what the world has accepted is really true? And if, as we see things today, these instances are considered fiction, can Chazal be blamed for ideas that were accepted by the naturalists of their times? And this is what really happened. These statements are to be found in the works of Pliny, who lived in Rome at the time the Second Temple was destroyed, and who collected in his books on nature all that was well known and accepted in his day.

(Trusting the Torah’s Sages, Chapter 4)

Rabbi Samson Raphael Hirsch explains that Chazal were simply giving a ruling for a case that was presented to them. They did not take it upon themselves to verify whether or not such creatures existed, just as the Torah scholars of Rabbi Hirsch’s day would readily accept the testimony of Alexander von Humboldt (1769-1859), a famous German naturalist. If we now think that such creatures never existed, it does not affect the standing of Chazal. (In contrast to this position is that of Rabbi Yehoshua Heller of Telz, who writes in his work Maoz Ha-Das that if Chazal describe such a creature, it must exist.)

As Rabbi Hirsch notes, for centuries, most information about the natural world was grounded in the writings of Pliny the Elder (23?-79 CE). He was a Roman civil servant and cavalry officer who collected stories about animals and believed everything he was told. Pliny took Aristotle’s Historia Animalium and extended it into the thirty-seven volume Historia Naturalis. This work contained an extraordinary range of superstitions and folklore about animals. Unfortunately, Pliny’s work became the standard reference upon which all future works were based. Thus, fantasy and folklore became widely accepted as fact.

Rabbi Aryeh Carmell suggested to me that the creature concerned is a mole. As it emerges from the earth, people could mistakenly believe that it is growing from the earth. The same could apply to the jerboa. Rabbi Mordecai Kornfeld suggested to me that the myth grew from the frogs that emerge from earth, as discussed earlier.

IV. Dong Chongs and Ear-Mice

Rabbi Samson Raphael Hirsch’s explanation concerning both the yidoni and the dirt-mouse is that Chazal simply gave the legal ruling concerning the creatures that were reported to exist; they did not investigate whether these reports were actually true. But the reason why they did not investigate these reports was not only for lack of resources. It was also because there was value to discussing such rulings. The study of Torah is not only for the purpose of practical law; it is an end unto itself.

The classical example of this is with ben sorer u’morer, the rebellious son who is put to death. The criteria for a child to be classified as a ben sorer u’morer are such that it is virtually impossible for such a case ever to actually occur. It is a practical impossibility, but we study its laws for the sake of the study itself. Even if there is no such creature as the earth-mouse or the vegetable-lamb, the study of their theoretical laws is still Torah.

An example of this approach is found in a Tosafos that discusses the usage of an animal as a cover for a coffin:

...But is it normal to make a cover for a coffin out of an animal?! The answer is that even though it is not normal to do so, we nevertheless find many unlikely cases that the Talmud discusses, in order to analyze them and be rewarded for this.

(Tosafos to Kesuvos 4b, s.v. Ad Sheyistam)

This also provides a response to Rabbi Heller’s argument in defense of such creatures that if the Torah discusses it, it must ipso facto exist. Ben sorer u’morer proves that the Torah includes, and even mandates, the discussion of cases that do not and cannot exist. The study of fictional cases is also Torah. And it may well have practical applications in cases that are yet to be discovered.

The Dong Chong

An example of why it may be relevant to discuss fictitious creatures that do not fall into just one of the, is the dong chong xia cao. In 1993, at the National Games in Beijing, China, three Chinese women long-distance runners set new world records for three different distances – the 10,000m, 15,000m and 30,000m. This outcome shocked the sports world and investigations ensued. It was discovered that their coach, along with his intensive training, was giving the runners an herbal tonic prepared with high concentration of the Chinese Cordyceps drug. Originally produced in Norway, but used in Chinese medicine for thousands of years, this immune-boosting, performance-enhancing compound was a trade secret until 1996, when the secret was uncovered. It comes from a creature that the Chinese call dong chong xia cao, which means “winter worm, summer grass.”

The bizarre facts of this is that the Hepialus moth, found only in the high and cold elevations of China's mountains, produces a soil-inhabiting caterpillar that becomes active in the late summer and eventually is infested by the Cordyceps fungus. At the beginning of autumn, the Cordyceps fungus releases its spores and invades the caterpillars. The fungus slowly eats away the tissues of the hibernating caterpillars throughout winter, filling them up with long filaments. By spring, the caterpillars sprout long stalks, which are revealed when the snow melts. (Source)

Thus, we see that it is possible for there to be a single unit that, in a way, is both a plant and an animal. The categories of animal, vegetable and mineral are not always as distinct as we would expect. The dong chong xia cao is not directly relevant to the Torah cases that we are discussing, but does provide a lesson in humility for the skeptic. One never knows when there might be a situation for which the cases discussed in the Torah would have a practical application.

The Ear Mouse

But there is an even more remarkable creature that may present a direct ramification of the halachah concerning the mouse that is part earth. This is not a species of creature, but rather a particular mouse, in the laboratory of University of Massachusetts anesthesiologist Dr. Charles Vacanti, that has a human ear growing on its back.

The mouse was created for children who lose their ears while fighting in school(!). Linda Griffith-Cima, an assistant professor of chemical engineering at M.I.T., created an ear-like scaffolding of porous, biodegradable polyester fabric. Then she and Vacanti distributed human cartilage cells throughout the form, and implanted the prototype ear on the back of a hairless mouse. The mouse, specially bred to lack an immune system that might reject the human tissue, nourished the ear as the cartilage cells grew to replace the fiber. The end result is a human ear that can be transplanted to the child that lost his own. The researchers said that the mouse remains healthy and alive after the ear is removed.

Figure : The remarkable ear-mouse

The ear-mouse may well fall into the category of the part-flesh, part-dirt mouse mentioned in the Mishnah – or at the very least, the discussions on the Mishnah would be highly relevant to this case. If this mouse were to die, which parts of it would render one tamei if touched? If the polyester fabric, implanted with human cartilage cells, is considered like earth, then one is not tamei if one touches it. This extraordinary case, unthinkable several years ago, serves to illustrate that discussing laws of creatures such as the dirt-mouse and the vegetable lamb, aside from their theoretical value of Torah study for its own sake, may as yet prove to have practical ramifications.

V. Conclusion

Spontaneous generation, a phenomenon accepted until a few centuries ago, and described in three cases in Torah literature, has been proven false. To deny this is to go against all reason. More recent Torah scholars have recognized this fact, and Chazal never considered themselves omniscient in the first place.

But those who would scoff at Torah literature for discussing such creatures are in error. They forget that they, too, would believe in such things, were it not for the accumulation of knowledge over the last few centuries. And it is always unwise to ridicule people’s knowledge of the natural world, as it is always full of surprises; who would have guessed that there is a caterpillar that grows like a plant?

Furthermore, these areas of Torah law have not been proven irrelevant. Torah study is relevant for its own sake, whether or not the cases it describes actually exist. Cases of spontaneous generation, true or false, serve all the better to plumb the depths of halachah.

And finally, one never knows when such halachic discussions will prove relevant. Does the ear on the back of the mouse at the University of Massachusetts transmit tum’ah? In determining the answer, the Mishnah’s discussion of the earth-mouse is the first place to look. The Sages may not have been correct when they said that lice spontaneously generate, but they were certainly correct when they said,

“Delve into the Torah again and again, for everything is in it.”

(Mishnah, Pirkei Avos 5:22)

© Nosson Slifkin 2001, www.zootorah.com

This essay is adapted from Rabbi Slifkin's book, Mysterious Creatures, soon to be published by Targum Press. It is printed here with permission.


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