Scientific Firsts

Horayot 10a ~ Halley's Comet, or Rabbi Yehoshua's Comet?

הוריות י,א

כי הא דר' גמליאל ורבי יהושע הוו אזלי בספינתא בהדי דר' גמליאל הוה פיתא בהדי רבי יהושע הוה פיתא וסולתא שלים פיתיה דר' גמליאל סמך אסולתיה דרבי יהושע אמר ליה מי הוה ידעת דהוה לן עכובא כולי האי דאיתית סולתא אמר ליה כוכב אחד לשבעים שנה עולה ומתעה את (הספינות) [הספנים] ואמרתי שמא יעלה ויתעה אותנו]

Rabban Gamliel and Rabbi Yehoshua were traveling together on a ship. Rabban Gamliel had sufficient bread for the journey, while Rabbi Yehoshua had bread and also some flour. [The journey lasted longer than expected, and] when Rabban Gamliel’s bread was finished he relied on Rabbi Yehoshua’s flour for nourishment. Rabban Gamliel said to Rabbi Yehoshua: How did you know from the outset that we would have such a substantial delay that you would need more flour? Rabbi Yehoshua said to Rabban Gamliel: There is one star that rises once in seventy years and misleads sailors at sea, causing their journeys to be extended. And I said: Perhaps that star will rise during our journey and mislead us.

Rabbi Yehoshua knew that a comet would likely be visible during his sea voyage, and that its light would confuse the sailors who navigated by the stars.  That comet returned about once every 70 years.  Does that remind you of anything?

Halley's Comet

Halley's comet last made an appearance in 1986. I remember looking up at the night sky with my father, and being thoroughly disappointed. Alas, the comet and the earth were on opposite sides of the sun, which made the quality of the appearance "the worst in two thousand years." 

Comet over 5th ave and Broadway.jpg

Other visits from Halley's comet were far more spectacular. In 1066 the comet was so bright that it was threaded onto the the 230 foot-long Bayeux Tapestry recording the Norman conquest of England. In 1531 it was seen for three weeks, and was visible even when the moon was full. And in 1910 the comet shone so brightly that it made its way onto postcards commemorating the spectacle.

The orbit of Halley's Comet. From  here .

The orbit of Halley's Comet. From here.

Renaming the comet for Rabbi Yehoshua

There are several claims for the oldest written description of Halley's Comet. The Chinese described its appearance as early as 240 BCE, and the Babylonians noted its appearance in 164 BCE on a on a cuneiform tablet now in the British Museum in London. The current record is a Greek sighting of the comet from 467BCE.  In contrast there is apparently no dispute about the earliest description of the length of the comet's orbit.  That accolade has been awarded to Edmund Halley who, using data from comet sightings in 1531, 1607 and 1682 suggested that the eponymous comet had a periodicity of about 76 years. But today's page of Talmud is clear: a comet with an orbit of about 70 years was identified by Rabbi Yehoshua. We know that "Halley's" Comet appeared in 66CE, when both Rabbi Yehoshua and Rabban Gamliel (II) were young men, and it must be to this comet that Rabbi Yehoshua referred.  Therefore it is Rabbi Yehoshua who should be honored with first describing the periodicity of the comet, and not Halley.  This is both self-evident and beyond question. It is also another of several examples which we have mentioned elsewhere in which scientific principles or facts were not properly attributed to the talmudic rabbis who first identified them. And so Talmudology is delighted to rename the comet Yehoshua's Comet.

Here's another fun fact about Rabbi Yehoshua's Comet of 66CE. It was described by the Jewish historian Josephus, who wrote that "a star resembling a sword stood over the city; a comet persisted for a long time." Josephus also recorded that the comet was seen during Pesach in 66CE. He wrote that it was taken as a good omen by those who started the Jewish rebellion against the Romans which lasted until the destruction of the Temple in 70CE.  And who was it who led another rebellion some sixty years later? Why, it was Bar Kochvah - the Son of the Star.

1835 - The First Hebrew Book about Halley's Comet

Hayyim Zelig Slonimski aged seventy-five. From   The Jewish Encyclopedia   ,  New York, Funk and Wagnalls, 1912.

Hayyim Zelig Slonimski aged seventy-five. From The Jewish Encyclopedia, New York, Funk and Wagnalls, 1912.

To coincide with the appearance of Halley's Comet in 1835, a Hebrew book called Kokhava Deshavit (The Comet) was published in Vilna. It described where and when the comet would be visible with precise coordinates for the inhabitants of Bialystok, as well as an explanation of the nature of comets and their orbits. The author was the remarkable Hayyim Zelig Slonimski, (1810-1904), the founding editor of Hazefirah (The Dawn), a weekly Hebrew-language newspaper first published in Warsaw in 1862. He also wrote Mosdei Hokhmah (The Foundation of Wisdom), a work on algebra, and struck up a friendship with the famed German naturalist and explorer Alexander von Humboldt (1769–1859). Not content with all this, Slonimski invented a method to send two telegraphs simultaneously over one wire (which was a very big deal at the time,) and developed a calculating machine that he later presented to the Imperial Academy of Sciences in St. Petersburg. It was so successful that in 1845 the Russian minister of education made Slonimski an honorary citizen, a remarkable honor given the general oppression faced by the Jews at the time.

Orbit of Halley’s Comet from  Kokhava Deshavit,  Vilna, 1835. Note that the outermost planet is Uranus. The second edition of the book (1857) described the discovery of Neptune in 1846. From the  Talmudology Library .

Orbit of Halley’s Comet from Kokhava Deshavit, Vilna, 1835. Note that the outermost planet is Uranus. The second edition of the book (1857) described the discovery of Neptune in 1846. From the Talmudology Library.

In Kokhava Deshavit Slonimski  explained Kepler's three laws of planetary motion, outlined Newton’s law of universal gravitation, and described the discovery of stellar aberration by the British astronomer James Bradley, which was an early, indirect proof of the validity of the heliocentric model of the solar system. After a description of each of the planets, Slonimski returned to the nature of comets in general and Halley’s Comet in particular. He described some of the astronomers whose findings helped explain what comets were, and ended with a depiction of the expected path of the comet.

In 1909 Mark Twain famously wrote that

I came in with Halley's Comet in 1835. It is coming again next year [1910], and I expect to go out with it. It will be the greatest disappointment of my life if I don't go out with Halley's Comet. The Almighty has said, no doubt: "Now here are these two unaccountable freaks; they came in together, they must go out together."

And he was right. He died on April 21, 1910, one day after the comet's closest approach to Earth. Twain thought the story of Halley's Comet was personal.  But Hayyim Slonimski knew that the story of the comet was national. He hoped that its reappearance would be celebrated by his descendants who had returned to their Jewish homeland. He ended his book describing how the comet would pass by the Earth, then circle behind the Sun, and then reappear sometime in March 1836. After that,

...it will continue along its path gradually becoming dimmer to the inhabitants of the Earth as it follows its orbit, until it will reappear [in 1910]. May it be then as a sign and wonder for our children after us in the Holy Land. Amen.

And so it was.

 

[For more about Hayyim Zelig Slonimski and his life as orthodox Jewish scientist, Talmudology is glad to offer this excerpt, taken from here.]

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Bava Basra 155b ~ Delayed Puberty in Boys

In today's page of Talmud we read about the treatment for the delayed onset of puberty:

כי אתו לקמיה דרבי חייא אי כחוש אמר להו זילו אבריוהו ואי בריא אמר להו זילו אכחשוהו דהני סימנין זמנין דנתרי מחמת כחישותא וזמנין דנתרי מחמת בריותא

Whenever people came to Rabbi Hiyya [with a case of a man who had not developed pubic hair]  he would tell them, if [the man was] thin, ‘Let him gain weight’; and if they were overweight he would say ‘Go lose weight’; for these signs [of sexual maturity] are sometimes delayed as a result of emaciation and sometimes  as a result of obesity.   (Yevamot 97a)

Rabbi Hiyya probably lived in the second half of the second century, and the treatment he suggested is one of the earliest examples associating nutritional status and delayed puberty.  Elsewhere in the Talmud we find this statement attributed to Rava, who died around 350 CE. But whoever suggested it first, I have found nothing in the works of Hippocrates, Aristotle and Galen that address this issue, so this association does not appear to have been a widely held belief in antiquity that was simply being echoed in the Talmud. 

There has been some discussion of what appears to be the increasingly earlier onset of puberty in girls. In fact, menarche, (the age of a girl's first menstrual period) has been steadily decreasing by a consistent three years per century of record keeping. However, R. Hiyya was addressing not the early onset of puberty in girls, but its delayed appearance in boys.  He noted that this delay was sometimes related to extremes of nutritional status, and so in these cases, was amenable to intervention.

R.Hiyya may have been the first first to report an association of obesity and delayed puberty in boys.

R.Hiyya was on to something. He (or Rava) may in fact have been the first to report an association between obesity and delayed puberty in boys.  This association has been confirmed by several studies which found that obesity has different effects on puberty in boys and girls. In girls, obesity is associated with earlier puberty, while in boys it has the opposite effect, and delays sexual maturation. But it was not until 2010 this association was confirmed by a longitudinal population-based study. This reported that a "higher BMI z score trajectory" (i.e. obesity)  during early to middle childhood may be associated with later onset of puberty among boys. 

The finding that puberty may be delayed in boys who are underweight has also been confirmed. As far as I can tell, none of the researchers has credited Rava (who died around 350 CE.) or Rabbi Hiyya for being the first to notice these associations. But they were first, and firsts count for something in science.

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Kiddushin 25a ~ Polydactyly

קידושין כה, א–ב

 א"ר חייא בר אשי אמר רב היתה לו יתרת וחתכה עבד יוצא בהן לחירות, אמר רב הונא והוא שנספרת על גב היד

Rav Hiyyah bar Ashi said in the name of Rav: if a slave had an extra finger and his master cut it off, the slave is freed on account of this act. Rav Huna said this only applies if the extra finger is in line with the others [lit. counted alongside the hand].  

Polydactyly (from the Greek daktylos, meaning finger), is a developmental abnormality in which there are more than the customary five fingers or toes at the end of the arms and legs. It has long been recorded in ancient civilizations - and is even mentioned in our own Hebrew Bible. Do you know who is described there as having a total of twenty four fingers and toes? (Click here to find out.)

Polydactyly is classified by the location of the extra digit: If it is found on the thumb or big toe, it is called preaxial polydactyly. If it is found on the the little (fifth) finger or toe it is called postaxial polydactyly.  Accessory digits in-between are classified according to their location and where they join the hand or finger. Syndactyly, on the other hand (!) occurs when there are fewer than five fingers or toes on each limb. (We will discuss syndactyly when we study tractate Bechorot, (daf 45a), on June 1st, 2019,  הבעל"ט.)

Rav Huna's Classification, and Swanson's classification

There are many different ways to classify polydactyly - although the most commonly used is the 1964 Swanson classification system, a modified version of which was adopted by the American Society for Surgery of the Hand and the International Federation of Societies for Surgery of the Hand in 1976. 

But Rav Huna, who died in Babylon around the year 296 CE, developed his own classification system long before Swanson, and it is based on simple observation: does the extra digit seem to begin in line with the other fingers, or does its origin seem to lie above them?  For Rav Huna, an extra digit that originated beyond the metacarpal-phalyngeal joint (the knuckle for our non-medical reader) in the hand, or beyond the metatarsal-phalageal joint in the foot did not have the legal status of a normal digit.  So an act of assault by the owner of a slave in which this kind of digit was amputated would not legally count as sufficient cause to allow the slave to gain his freedom.  With this information, look at the drawings below and decide in which case the loss of the extra digit would be sufficient cause for the slave to be freed.

Various forms of postaxial (ie. not on the big toe) Type A polydactyly of the foot, ranging from a partially duplicated fifth intermediate phalanx (top left) to a fully developed sixth digit, including the metatarsal (bottom right). From Case DT. Hill RJ. Merbs CF. Fong M. Polydactyly in the Prehistoric American Southwest.    Journal of Osteoarchaeology   2006: 6: 221–235.

Various forms of postaxial (ie. not on the big toe) Type A polydactyly of the foot, ranging from a partially duplicated fifth intermediate phalanx (top left) to a fully developed sixth digit, including the metatarsal (bottom right). From Case DT. Hill RJ. Merbs CF. Fong M. Polydactyly in the Prehistoric American Southwest.  Journal of Osteoarchaeology 2006: 6: 221–235.

If the slave had an extra fifth toe outlined in Figures 2-6, its loss would result in the slave going free. In all these cases, the extra digit arises in line with the base the the other toes (and in Figure 6, the extra toe is joined to an extra metatarsal). But in Figure 1, the extra fifth digit arises from the distal end of the fifth distal phalange (or, for our non-medical reader, the tip of the pinky); in this case its traumatic amputation by the slave's owner would not result in the slave gaining his freedom. 

This categorization appears to be another previously unrecognized medical first in the Talmud: Rav Huna's classification of polydactyly.   

היתה לו אצבע יתירה וחתכה, אם עומדת בסדר האצבעות יוצא לחירות
— שולחן ערוך יורה דעה הלכות עבדים סימן רסז סעיף כט
Polydactylous feet from Newspaper Rock in Indian Creek State Park, Utah. These carvings in rock are called petroglyphs, and were made by native Americans as long as  1,500  years ago .

Polydactylous feet from Newspaper Rock in Indian Creek State Park, Utah. These carvings in rock are called petroglyphs, and were made by native Americans as long as 1,500  years ago.

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Kiddushin 16b ~ Measuring Puberty

קידושין טז, ב

בן תשע שנים שהביא שתי שערות שומא מבן ט' שנים ויום אחד עד בן י"ב שנה ויום אחד ועודן בו שומא ר' יוסי בר' יהודה אומר סימן בן י"ג שנה ויום אחד דברי הכל סימן 

If a nine year old grows two hairs [in the pubic region] the growth should be attributed to a mole [and not as a sign of sexual maturity]. [If these hairs grow] from the age of nine years and one day until twelve years and one day, and they are still there [when the child reaches twelve, one opinion is that they should be attributed to a] mole, and Rabbi Yossi bar Rabbi Yehuda says they are a sign of sexual maturity. [If these hairs grow] when the child is thirteen years old and one day, then everyone agrees they are a sign of sexual maturity...(Kiddushin 16b)

Pre-Modern Descriptions of Puberty

The way in which children develop into adults has fascinated us for centuries.  In fact, the earliest surviving statement on human growth dates back to the sixth century BCE, (not long after the prophet Jeremiah lived) and is by the Athenian poet Solon. One critic described his poem as combining "scientific sense with philosophical probability (if not, regrettably, with poetic elegance)." Here is Solon:

A young boy acquires his first ring of teeth as an infant and sheds them before he reaches the age of seven years.  When the god brings to an end the next seven year period, the boy shows the signs of beginning puberty. In the third hebdomad, [ a period of seven years] the body enlarges, the chin becomes bearded and the bloom of the boy's complexion is lost. In the forth hebdomad physical strength is at its peak and is regarded as the criterion of manliness; in the fifth hebdomad a man should take thought of marriage and seek sons to succeed him. In the sixth hebdomad a man's mind is in all things disciplined by experience and he no longer feels the impulse to uncontrolled behavior. In the seventh he is at his prime in mind and tongue and also in the eighth, the two together making fourteen years. In the ninth hebdomad, though he still retains some strength, he is too feeble in mind and speech for the greatest excellence. If a man continues to the end of the tenth hebdomad, he has not encountered death before due time. 

Hippocrates believed that puberty could be delayed in areas where "the wind is cold and the water is hard". Rabbi Shimon ben Gamliel (d. 70CE) would have agreed, because he thought that the growth of pubic hair was hastened in those who used the bathhouse regularly.  But it is especially interesting to compare Aristotle's writings on puberty with those of the Talmud (which of course were codified several hundred years later).

In man, maturity is indicated by a change in the tone of the voice, by an increase in size and an alteration in appearance of the sexual organs, and also by an increase in size and alteration in appearance of breasts, and above in the hair growth above the pubes.

Aristotle (d. 322 BCE) seems to have put a lot of weight on the growth of pubic hair, just like the rabbis of  in the Talmud did many years later. Galen, who died in 199 CE, was cautious about timing the onset of puberty: "Some begin puberty at once on the completion of the fourteenth year, but some begin a year or more after that" (De Sanitate Tuenda, or p288 of this translation). Jumping forward several centuries, we find that girls in Tuscany in 1428 were allowed to marry aged eleven and a half, although they were forbidden to live with their husbands until they were twelve. However the Bishop of Florence (later canonized as Saint Anthony) declared that cohabitation was allowed "provided the girl had reached puberty." 

The Tanner Scale

Today, the stage of sexual maturity in children is most commonly measured using the Tanner scale, described by the British pediatrician James Tanner, who died in 2010.  (He wrote a fascinating History of the Study of Human Growth as a sort of a hobby, but his day job was working as a Professor at the Institute of Child  Health in London.)  Here is how Tanner described his scale in boys, (from his original paper published in 1970):

Stage 1: Pre-adolescent. The velus [sic] over the  pubes is no further developed than that over the abdominal wall, i.e. no pubic hair.
Stage 2: Sparse growth of long, slightly pigmented downy hair, straight or slightly curled, appearing chiefly at the base of the penis. This stage is difficult to see on photographs, particularly of fair-headed subjects...
Stage 3: Considerably darker, coarser, and more curled. The hair spreads sparsely over the junction of the pubes. This and subsequent stages were clearly recognizable on the photographs.
Stage 4: Hair is now adult in type, but the area covered by it is still considerably smaller than in most adults. There is no spread to the medial surface of the thighs.
Stage 5: Adult in quantity and type, distributed as  an inverse triangle of the classically feminine pattern. Spread to the medial surface of the thighs but not up the linea alba or elsewhere above the base of the inverse triangle.
There has been less discussion in the literature as to whether the appearance of pubic hair has advanced in females, although this does seem to be the case, pubarche having advanced by at least 6 months. The PROS study found stage II pubic hair to be apparent in African-American females at a mean age of 8·78 years and 10·51 years in whites.
— Slyper, AH.The pubertal timing controversy in the USA, and a review of possible causative factors for the advance in timing of onset of puberty. Clinical Endocrinology (2006) 65, 1–8

Tanner also described other signs of sexual maturity, since growth of pubic hair is not the only maker.  In boys, for example, Tanner used a five-stage system for genital growth: in stage one, the  "testes, scrotum, and penis are of about the same size and proportion as in early childhood," whereas in stage two, "the scrotum and testes have enlarged and there is a change in the texture of the scrotal skin..."  Tanner noted that the stages of pubic hair development and the stages of genital development differ, so that a boy may reach full genital maturation sooner than he reaches stage five on the pubic hair scale.  

From Marshall A. Tanner JM. Variations in the pattern of pubertal changes in boys.   Archives of Disease in Childhood   1970. 45: 13-25.

From Marshall A. Tanner JM. Variations in the pattern of pubertal changes in boys. Archives of Disease in Childhood 1970. 45: 13-25.

Tanner's work reveals what we already know intuitively. Maturity, whether sexual or emotional, is a process that takes time and proceeds through many stages. The rabbis of the Talmud relied predominantly on one marker of adulthood:  sexual maturity as evidenced by a minimal of pubic hair growth.  But they used it in conjunction with the age of the child.  They also understood that the onset of these signs might be sooner in some children and later in others.

Sequence of events in puberty in girls (top) and boys. From Marshall A. Tanner JM. Variations in the pattern of pubertal changes in boys.    Archives of Disease in Childhood    1970. 45:22.

Sequence of events in puberty in girls (top) and boys. From Marshall A. Tanner JM. Variations in the pattern of pubertal changes in boys. Archives of Disease in Childhood 1970. 45:22.

In most European countries, the age of the onset of puberty (as measured by the onset of menstruation) has fallen by about a year per century. Boys also seem to be developing earlier than previously, possibly by more than a year. Data from the US National Health and Nutrition Examination Survey (NHANES III) study of boys aged 8 –19 years, suggests that the mean age of onset of male genital development based on visual inspection is now about nine years for African-Americans and ten years for white boys.

Another First?

Last year we analyzed talmudic statements of R. Hiyya (who lived in the second half of the second century,) and Rava, (d. 350CE) who appear to have been the first to report an association between obesity and delayed puberty in boys.  They claimed that puberty may be delayed in boys who are underweight, and this association has now been confirmed. As we noted then, none of the researchers has credited these talmudic sages for being the first to notice these associations. But Rava and R. Hiyya were first, and firsts count for something in science. The Baraita in today's daf  may be the first recorded discussion of the lower limits of sexual maturity. But the rabbis of the Talmud used other markers of maturity, like breast development which is discussed in Masechet Niddah (47a).They distinguished between "lower" and "upper" signs of puberty, and so presaged the work of Tanner. (The rabbis also ruled that "all girls who are examined are examined by women". Thank heavens.)

There were several reasons why the Talmud had to codify the stages of physical maturity.  Among these were to allow a father to decide to whom his daughter would marry.

A father who declares...my daughter is twelve years and a day is believed in order to marry the child off...(רמב׳ם הל׳ אישות ב:כג)

Today, any notion that a child under the age of twelve (or sixteen for that matter) would be mature enough to marry is utterly repugnant to us. But according to the UN in developing countries, one in every three girls is married before reaching the age of eighteen, and one in nine is married by the age of fifteen.  When we read the Talmud we often get a glimpse into a Jewish world very different from our own. But some practices of that world still exist outside of the Jewish community today, to the shame of us all. 

From United Nations Children’s Fund, Ending Child Marriage: Progress and prospects, UNICEF, New York, 2014.

From United Nations Children’s Fund, Ending Child Marriage: Progress and prospects, UNICEF, New York, 2014.

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