Bava Basra 25b ~ The Sun's Orbit Around the Earth

בבא בתרא כה, א–ב

תניא ר"א אומר עולם לאכסדרה הוא דומה ורוח צפונית אינה מסובבת וכיון שהגיעה חמה אצל קרן מערבית צפונית נכפפת ועולה למעלה מן הרקיע ורבי יהושע אומר עולם לקובה הוא דומה ורוח צפונית מסובבת וכיון שחמה מגעת לקרן מערבית צפונית מקפת וחוזרת אחורי כיפה 

Rabbi Eliezer taught: The world is similar to a partially enclosed veranda [אכסדרה], [which is enclosed on three sides] and the northern side of the world is not enclosed with a partition like the other directions. When the reaches the northwestern corner it turns around and ascends throughout the night above the rakia [to the east side and does not pass the north side].

Rabbi Yehoshua says: The world is similar to a small tent [קובה], [and the north side is enclosed too,] and when the sun reaches the northwestern corner it orbits and passes behind the dome.

The monthly movement of the Earth, Moon, and Sun, according to Moses Hefez, Melekhet Mahashevet, Venice, 1710. From here. 

In this passage the path of the Sun is described, and to understand it you need to know this. The rabbis of the Talmud believed that the earth was a flat disc, and that above the sky was an opaque covering called the rakia. During the day the Sun was visible under the rakia, and then at night it zipped back from where it set in the west to where it would rise again in the east by traveling over the rakia. Something like this: 

From Judah Landa. Torah and Science. Ktav 1991. p66.

The other place that you will find the path of the Sun discussed in the Talmud is in Pesachim 94b.  Here is the text:

חכמי ישראל אומרים ביום חמה מהלכת למטה מן הרקיע ובלילה למעלה מן הרקיע וחכמי אומות העולם אומרים ביום חמה מהלכת למטה מן הרקיע ובלילה למטה מן הקרקע א"ר ונראין דבריהן מדברינו שביום מעינות צוננין ובלילה רותחין

The wise men of Israel say that during the day the Sun travels under the rakia, and at night it travels above the rakia. And Gentile wise men say: during the day the Sun travels under the rakia and at night under the Earth. Rabbi [Yehudah Hanasi] said: their view is more logical than ours for during the day springs are cold and at night they are warm.

From this is discussion it is once again apparent that in the talmudic view, the sky must be completely opaque. As the Sun passes over the top of the sky at night, it is not in the slightest way visible.

Also from Landa, p63

It is hardly news to point out that a long time ago people believed that the universe was different to the way that we understand it to be today. But the belief of the rabbis of the Talmud was standard until only very recently, by which I mean only a few hundred years. 

Copernicus and his critics

When Nicolas Copernicus (d. 1543)  proposed his heliocentric universe he did so for a number of mathematical reasons but without any evidence. The experimental evidence that supported his claim did not appear for over three hundred years, when in 1838 the first measurement of stellar parallax occurred. Without evidence to support the Copernican model, many rejected it.  For example, the famous Danish astronomer Tycho Brahe (1546–1601) rejected the Copernican model, and came up with one of his own in which all the planets orbited the sun, which in turn dragged them around a stationary earth. For about one hundred years after Copernicus, the universities of Oxford and Cambridge ignored the heliocentric model entirely, and the English philosopher, statesman, and member of Parliament Francis Bacon (1561–1626) rejected the Copernican model as having “too many and great inconveniences.”

Galileo and the Catholic Church

Galileo published his discovery of the four satellites of Jupiter in Sidereus Nuncius in 1610. This discovery did not prove that Copernicus was correct, but it lent a great deal of corroborative evidence to the Copernican model. In addition Galileo noted that Venus seemed to change shape, just as the Moon did, sometimes appearing almost (but never quite) full, sometimes as a semi-circle, and at other times as sickle-shaped. The best explanation was that Venus was not orbiting the earth, but that it was in fact orbiting the Sun. And that turned out to be correct too. But as we know, things didn't tun out to well for Galileo. The Catholic Church, which by now had placed Copernicus' book on its Index of Banned Books, also banned Galileo's Dialogue Concerning the Two Chief World Systems - the book in which he outlined his proofs that the earth orbited the sun. The works of the astronomer Johannes Kepler (d.1630) were also added to the Index.  

The Jesuit Edition of Newton's Principa

In 1687 the Copernican model found support with the publication of Newton’s Principa Mathematica. In that work, Newton described the universal laws of gravitation and motion that were behind the observations of Copernicus, Galileo, and Kepler.  The book went through three Latin editions in Newton’s life-time, and an English edition was published two years after his death in 1727.  A new three-volume edition of the Principia was published in Geneva between 1739 and 1742.  This edition contained a commentary on each of the book’s propositions by two Franciscan friars but was noteworthy for another reason. In its final volume, the “Jesuit edition”  contained a disclaimer by the friars distancing themselves from the heliocentric assumptions contained in the book:

Newton in this third book assumes the hypothesis of the motion of the Earth. The propositions of the author cannot be explained otherwise than by making the same hypothesis. Hence we have been obliged to put on a character not our own. But we profess obedience to the decrees promulgated by sovereign pontiffs against the motion of the Earth.

So it wasn't just the rabbis of the Talmud who believed the earth stood still.  In fact they believed what (nearly) every one else continued to believe for at least a thousand years. The sun certainly looks like it revolved around the earth, so they created a model of the universe in which it did so, either by circling under the earth at night, or by zig-zagging back across the top of the rakia. Neither model turned out to be correct.  But in believing this, the rabbis were firmly in the majority.

[If you want more on this subject, Natan Slifkin has an excellent monograph on the Path of the Sun at Night. I'm also told there's an excellent book on the Jewish reception of Copernican thought.]

Bava Basra 24a ~The Chatam Sofer, Rationalism, and Anatomy That Isn't There

In August 2013 a paper published in the otherwise sleepy Journal of Anatomy caused quite a sensation. Although doctors have been dissecting the human body for centuries, it seems that they missed a bit, and a team from Belgium announced that they had discovered a new knee ligament, which they called the anterolateral ligament. On today’s page of Talmud the rabbis describes the opposite phenomena. In it, the rabbis describe an anatomical part that is really hard to identify, and may not exist at all.  It is called the aliyah, which usually refers to an attic or the upper chamber of a house.

PROXIMITY or Majority?

The rabbis are trying to resolve the issue of who owns a dove found between two dove cots. How far could it hop, and what difference might that make with regards the decision?

בבא בתרא כג, ב

ניפול הנמצא בתוך חמשים אמה הרי הוא של בעל השובך חוץ מחמשים אמה הרי הוא של מוצאו נמצא בין שני שובכות קרוב לזה שלו קרוב לזה שלו מחצה על מחצה שניהם יחלוקו

With regard to a dove chick [nippul] that was found within fifty cubits of a dovecote, it belongs to the owner of the dovecote.If it was found beyond fifty cubits from a dovecote, it belongs to its finder.In a case where it was found between two dovecotes, if it was close to this one, it belongs to the owner of this dovecote; if it was close to that one, it belongs to the owner of that dovecote. If it was half and half, [i.e., equidistant from the two dovecotes,] the two owners divide the value of the chick.

Fair enough. But Abbaye, the great fourth century Babylonian sage had a different take. Perhaps we should not be concerned with proximity, but instead be concerned with who owns the majority of the doves in the area. And brings a proof that will surprise you.

אמר אביי אף אנן נמי תנינא דם שנמצא בפרוזדור ספיקו טמא שחזקתו מן המקור ואע"ג דאיכא עלייה דמקרבא

Abaye said: We learn in a Mishnah (Niddah 17b) as well that one follows the majority rather than proximity: With regard to blood that is found in the corridor [baperozdor],i.e., the cervical canal, and it is uncertain whether or not it is menstrual blood, it is ritually impure as menstrual blood, as there is a presumption that it came from the uterus, which is the source of menstrual blood. [And this is the halakha even though there is an upper chamber, which empties into the canal, which is closer.]

Here is that Mishnah in full:

נדה יז, ב

משל משלו חכמים באשה החדר והפרוזדור והעלייה דם החדר טמא דם העלייה טהור נמצא בפרוזדור ספקו טמא לפי שחזקתו מן המקור

The Sages had a parable with regard to the structure of the sexual organs of a woman [based on the structure of a house]: The inner room represents the uterus, and the corridor [perozdor] leading to the inner room represents the vaginal canal, and the upper story represents the bladder. 

Blood from the inner room is ritually impure. Blood from the upper story is ritually pure. If blood was found in the corridor, there is uncertainty whether it came from the uterus and is impure, or from the bladder and is pure. Despite its state of uncertainty ,it is deemed definitely impure, due to the fact that its presumptive status is of blood that came from the source ,i.e., the uterus, and not from the bladder. 

What anatomy is being discussed here? In particular, what is the aliyah, the “attic” of female genital anatomy? It turns out to be complicated.

the Aliyah surrounds the ovaries

From the Mishanh in Niddah, it is clear that the aliyah sometimes bleeds, and that this blood becomes visible when it passes into the vagina. Maimonides identifies the aliyah with the space that contains the ovaries and the fallopian tubes. In modern medicine the ovaries and the Fallopian tubes and tissues that support them are called the adenxa. They are further from the vagina that the uterus, and so this identification does not fit in with Abaye's anatomy in which the aliyah is closer to the vagina than is the uterus.

רמב׳ם הל׳ איסורי ביאה ה, ד

ולמעלה מן החדר ומן הפרוזדוד, בין חדר לפרוזדוד, והוא המקום שיש בו שתי ביצים של אישה, והשבילים שבהן מתבשלת שכבת זרע שלה--מקום זה הוא הנקרא עלייה.  וכמו נקב פתוח מן העלייה לגג הפרוזדוד, ונקב זה קוראין אותו לול; והאבר נכנס לפנים מן הלול, בשעת גמר ביאה

Above the uterus and the vagina, between the uterus and the vagina, is the place in which the two ovaries are found, and the tubes along which the sperm from intercourse matures, this place is called the aliyah. (Maimonides, Mishneh Torah Issurie Bi'ah 5:4)

As we said, the problem is that the space which contains the ovaries is inside the abdomen, and this space does not connect with the vagina. It connects via the Fallopian tubes with the uterus.  Although Maimonides does not identify the aliyah as the ovaries themselves, some have done so. But the problem with this is that the ovaries don't bleed unless they develop a large cyst which then ruptures. But even in this case they bleed into the abdomen, or into the uterus, again via the Fallopian tubes, and not directly into the vagina.

Menachem ben Shalom (1249-1306) known as the Meiri, wrote an important commentary on the Talmud call Bet Habechirah - בית הבחירה and in it he too identifies the aliyah as the space between the uterus and the vagina in which the ovaries are found. He notes that in this space there are many blood vessels which may rupture and bleed directly into the vagina (עורקים שמתבקעים לפעמים), but as we have noted this is not biologically correct. Any bleeding from the adnexa is via the Fallopian tubes into the uterus itself, and certainly not directly into the vagina.

The Aliyah is the vagina

In his classic Biblisch-Talmudische Medezin published in 1911, Jacob Preuss identified the aliyah as the vagina. "It can be assumed with reasonable certainty" he wrote "that the cheder refers to the uterus, that the prosdor is the vulva, and that the aliyah is the vagina." However certain he may have been, Preuss is the only one to make this identification, which does not fit in with the text of the Mishanh. So let's try another suggestion.

The Aliyah is the Bladder

Sefer Ha'Arukh, Venice 1552.

Natan ben Yechiel of Rome, who died in 1106, wrote an influential lexicon of talmudic terms called the Sefer Ha'Arukh (ספר הערוך) which was first published around 1470. In that work the aliyah is identified as the urinary bladder. This identification also cannot be correct, because the bladder does not empty into the vagina, and because it does not lie between the uterus and the vagina but anterior to them. The commentary in the Schottenstein Talmud to Niddah 17b notes that a connection between the urethra and the vagina (known as a urethero-vaginal fistula) might account for bleeding from the bladder into the vagina. This is possible - though it is of course not normal anatomy.  

From here.

The AliyaH is a completely new structure

Meir ben Gedaliah of Lublin (d.1616) also considered the location of the aliyah in his modestly titled book Meir Einei Hakhamim - מאיר עיני חכמים - (Enlightening the Eyes of the Sages) first published in Venice in 1618.  He locates it between the uterus and the bladder, and provides two helpful schematics. The problem is that there is no such organ. You won't find it if you dissect a cadaver, and you won't find it in any textbook of anatomy (like this one). And as one astute radiologist and reader of Talmudology recently told me, you won't find it on an MRI either. Here is the text. 

Maharam Lublin. Meir Einei Hakhamim. Venice 1618. p255b.

This non-existent anatomy is also pictured in the Schottenstein Talmud (Niddah 17b), based on the difficult Mishanah.  

From Schottenstein Talmud Niddah 17b. Note that this does NOT correspond to the known female anatomy, but is a schematic based on Rashi's understanding.

The CHatam Sofer on the Aliyah

Moses Schreiber known as Chatam Sofer, (d. 1839) was a leader of Hungarian Jewry and he too weighed in on the issue in his talmudic commentary to Niddah (18a).

What is the "corridor" or the "room" or the "roof" or the "ground" or the "aliyah" ? After some investigation using books and authors experts and books about autopsies it is impossible to deny the facts that do not accord with the statements of Rashi or Tosafot or the diagrams of the Maharam of Lublin...but you will find the correct diagram in the book called Ma'asei Tuviah and in book Shvilei Emunah...therefore I have made no effort to explain the words of Rashi or Tosafot for they are incompatible with the facts...

Tuviah HaCohen, the Doctor from Padua

I couldn't find the diagram in any edition of the Shvilei Emunah to which the Chatam Sofer refers, so let's look at the diagram from Ma'asei Tuviah, which I happen to have in my own library.

Detail from Tuviah HaCohen, Ma'aseh Tuviah, Venice 1708. p132b.

A careful reading of the annotation (זז) reveals that Tuviah HaCohen (1652-1729) identifies the aliyah as that area containing the ovaries and the Fallopian tubes. In doing so he followed the opinion of Maimonides that we cited earlier, even though that does not in any way fit in with the understanding of Abaye and his ruling that blood found in the vagina that comes from the aliyah is not impure because it does not come from the uterus. Any gynecologist (or first year medical student completing their anatomy dissections) will tell you that blood from the adnexa (the ovaries and Fallopian tubes) can only get into the vagina via the uterus. But the most interesting part of this diagram is the very first line of text, at the top of the image. 

פירוש המחבר כפי ידיעת הנתוח  

The author's explanation according to knowledge gained from an autopsy

Anatomical Theatre, Palazzo del Bo, at the University of Padua. It was built in 1594 by the anatomist who helped found modern embryology, Girolamo Fabricius. From here.

Here, perhaps for the first time, anatomical knowledge from an autopsy is being shared in Hebrew. At the medical school in Padua, two bodies (one of each sex) had to be dissected each year, and all the students attended- Tuviah included.  As a medical student, Tuviah would have stood in the famous anatomical theater and watched the dissection, perhaps following along in one of the textbooks based on those dissections. 

Facts Matter

As the Chatam Sofer noted, facts matter. The illustration in the work of the Maharam of Lublin was an example of trying to get the facts to fit the text of the Mishnah (or more precisely, the explanations of Rashi and Tosafot) but in doing so the Maharam created a fictitious anatomical part.

It is very unlikely that the rabbis of the Talmud witnessed human dissections. In the ancient world two Greeks, Herophilus of Chalcedon and  Erasistratus of Ceos (who lived in the first half of the third century BCE) were "the first and last ancient scientists to perform dissections of human cadavers." Facts about human anatomy became clear once human dissection began in the fourteenth century, but as is demonstrated by the Maharam of Lublin, these lessons did not always diffuse into the Jewish community.  The Chatam Sofer is often - and rightly  - cited as a force for tradition against the challenges from the outside world. But the Hatam Sofer, at least in so far as gynecology was concerned, had no time for a theory when the facts show otherwise. In an age of "alternative facts" the Chatam Sofer is a model of rationalism.

Bava Basra 20a ~ A Baby Born After Eight Months

Getty Images

A Baby at the Window

In tomorrow's page of Talmud we read a list of objects which, if placed in an opening between rooms, blocks the tumah (ritual impurity) from passing from one room into the next. Among that list is a baby born after only eight months of gestation:

בבא בתרא כ, א

 עשבין שתלשן והניחן בחלון או שעלו מאליהן בחלונות ומטלוניות שאין בהן שלש על שלש והאבר והבשר המדולדלין בבהמה ובחיה ועוף ששכן בחלון ועובד כוכבים שישב בחלון ובן שמנה המונח בחלון והמלח וכלי חרס וספר תורה כולם ממעטין בחלון 

Grass that was plucked and placed in an opening, or grass that grew by itself in an opening; scraps of fabric that are smaller than three by three fingerbreadths; a partially severed limb or a piece of flesh hanging from a domestic or a wild animal; a bird resting in an opening; an idol worshipper sitting in an opening; a baby born after only eight months of gestation lying in an opening; salt, earthenware vessels and a Torah scroll -all of these reduce the size of the opening and so prevent the tumah from passing through it.

The Talmud then questions this ruling about the premature child lying on a window between two rooms, one if which contains a source of tumah. Won't the mother of the baby carry the child away? How then can we suggest it will be a barrier to the tumah? The Talmud, as always, has a solution: the case is regarding a child born prematurely on Shabbat. Such a child is mukzteh, that is, it is in a category of objects that must not be moved on Shabbat: 

דתניא בן שמנה הרי הוא כאבן ואסור לטלטלו בשבת

For it was taught in a Braisa. A baby born at eight months of gestation is treated like a stone

[on Shabbat, because it is muktzeh.]

The premature baby is given the status of a stone because it was not considered to be viable, and as a non-viable human being it does not contract ritual impurity. So that's why the premature baby is listed along with grass, idol worshippers, and the severed limbs of cattle as preventing the transmission of tumah. Got it?

When we studied Yevamot we came across another case which pivoted on the viability of babies born at seven vs. eight months of gestation. The question there was about proving the paternity of a child, and the discussion hinges on the belief that while a child born after seven months of gestation would be viable, a child born at eight months gestation would not be so.  Rashi noted the following: בר תמניא לא חיי -  "an eight month fetus cannot survive." And so now we can ask, where on earth does this notion come from? 

Seven vs Eight Months of gestation in antiquity

Homer's Iliad, written around the 8th century BCE,  records that a seven month fetus could survive. But it is not until Hippocrates (c. 460-370 BCE, or some 500 years before Shmuel), that we find a record of the belief that a fetus of eight months' gestation cannot survive, while a seventh month fetus (and certainly one of nine months gestation) can.  His Peri Eptamenou (On the Seventh Month Embryo) and Peri Oktamenou (On the Eight-Month Embryo) date from the end of the fifth century BCE, but this belief is viewed with skepticism by Aristotle.

In Egypt, and in some other places where the women are fruitful and are wont to bear and bring forth many children without difficulty, and where the children when born are capable of living even if they be born subject to deformity, in these places the eight-months' children live and are brought up, but in Greece it is only a few of them that survive while most perish. And this being the general experience, when such a child does happen to survive the mother is apt to think that it was not an eight months' child after all, but that she had conceived at an earlier period without being aware of it.

The belief that an eight month fetus cannot survive has a halakhic ramification: Maimonides ruled that if a boy was born prematurely in the eighth month of his gestation and the day of his circumcision (eight days after his birth) fell out on shabbat, the circumcision - which otherwise would indeed occur on Shabbat, is postponed until Sunday, the ninth day after his birth. 

רמב׳ם הל' מילה יד, א

מי שנולד בחדש השמיני לעבורו קודם שתגמר ברייתו שהוא כנפל מפני שאינו חי... אין דוחין השבת אלא נימולין באחד בשבת שהוא יום תשיעי שלהן

A child born after eight months of gestation before being fully formed is treated as a stillbirth because it will not live...and we do not set aside the laws of Shabbat [to circumcise him] but he is circumcised on Sunday, which is the ninth day of his life.

This belief persisted well into the early modern era. Here is a state–of–the–art medical text published in 1636 by John Sadler.  Read what he has to say on the reasons that an eight month fetus cannot survive (and note the name of the publisher at the bottom of the title page-surely somewhat of a rarity then): 

Saturn predominates in the eighth month of pregnancy, and since that planet is "cold and dry"," it destroys the nature of the childe". That, or some odd yearning of the child to be born in the seventh but not the eight month (according to Hippocrates) is the reason that a child born at seven and nine months' gestation may survive, but not one born at after only eight months. 

Evidence from Modern Medicine

Today we know that gestational length is of course critical, and that, all things being equal, the closer the gestational length is to full term, the greater the likelihood of survival. We can state with great certainty, that an infant born at 32 weeks or later (that's about eight months) is in fact more likely to survive than one born at 28 weeks (a seven month gestation.) In fact, a seven month fetus has a survival rate of 38-90% (depending on its birthweight), while an eight month fetus has a survival rate of 50-98%. Here is the data, taken from a British study.

Draper, ES, Manktelow B, Field DJ, James D. Prediction of survival for preterm births by weight and gestational age: retrospective population based study British Medical Journal 1999; 319:1093.

More recently, a study from the Technion in Haifa showed that even the last six weeks of pregnancy play a critical role in the development of the fetus. This study found a threefold increase in the infant death rate in those born between  34 and 37 weeks when compared full term babies.  

You can read more on the history of the eight month fetus in a 1988 paper by Rosemary Reiss and Avner Ash.  From what we have reviewed, the talmudic belief that a seven month fetus can survive but an eight month fetus cannot is one that was widely shared in the ancient world, and even in the early modern era.  But all the evidence we have today firmly demonstrates that it is simply not true.

[Repost in part from Yevamot 42.]

Bava Basra 16b ~ Here Comes the Sun

בבא בתרא טז, ב 

רבי שמעון בן יוחי אומר אבן טובה היתה תלויה בצוארו של אברהם אבינו שכל חולה הרואה אותו מיד מתרפא ובשעה שנפטר אברהם אבינו מן העולם תלאה הקדוש ברוך הוא בגלגל חמה אמר אביי היינו דאמרי אינשי אידלי יומא אידלי קצירא

Rabbi Shimon ben Yochai said: there was a precious stone that hung from the neck of Abraham our forefather. Any sick person who looked at it was instantly cured.  When Abraham our forefather died, the Holy One, Blessed be He, hung this stone in the orb of the sun. Abaye said, this is what is meant by the popular saying "when the sun is lifted, sickness is lifted"

Abaye, the great Babylonian sage of the fourth century, commented on a statement made Rabbi Shimon ben Yochai about two centuries earlier, and suggested that sunlight helps heal.  This was not the only time Abaye opined about the health benefits of sunlight. We came across another example when we studied Nedarim: 

נדרים  ח, ב

שמש צדקה ומרפא אמר אביי ש"מ חרגא דיומא מסי ופליגא דר"ש בן לקיש דאמר אין גיהנם לעולם הבא אלא הקב"ה מוציא חמה מנרתיקה צדיקים מתרפאין בה ורשעים נידונין בה

“The sun of righteousness, with healing in its rays” (Malachi 3:20)...Abaye said: “We learn from here that the dust of the sun heals”…Rabbi Shimon ben Gamliel said, “there is no hell in the world to come. Rather God takes the sun out of its canopy; the righteous are healed by it and the wicked are punished by it” (Nedarim 8b.)

A HISTORY OF HELIOTHERAPY

In 1903, the Nobel prize for Medicine was awarded to a Dane named Niels Finsen. Finsen had invented a focusable carbon-arc torch to treat – and cure – patients with lupus vulgaris, a painful skin infection caused by tuberculosis.  While this was the start of the modern medical use of phototherapy, using the sun as a source of healing is much, much older. Older even than the Talmud, which mentions it in today’s daf. 

“The Nobel Prize in Physiology or Medicine 1903 was awarded to Niels Ryberg Finsen “in recognition of his contribution to the treatment of diseases...with concentrated light radiation, whereby he has opened a new avenue for medical science”

Perhaps the earliest reference to heliotherapy – that is, using sunlight to heal - is found in Egyptian papyrus records from over 3,500 years ago, which record using the sun, together with ingesting a local weed, to treat skin conditions. The active ingredients of that weed, Ammi majus, were isolated in 1947. These ingredients, together with heliotherapy, were used in the first clinical trials to treat vitiligo, which were conducted, rather fittingly, in Egypt.  Further work determined that it was only a narrow part of the sun’s spectrum that was needed to treat vitiligo, psoriasis, and other skin conditions, and so lamps were developed that produced only narrow band ultraviolet light (UVB). These UVB lamps are now a mainstay of treatment for psoriasis.

“For most white people, a half-hour in the summer sun in a bathing suit can initiate the release of 50,000 IU (1.25 mg) vitamin D into the circulation within 24 hours of exposure”

— — Environmental Health Perspectives 2008:116;4. A162

SUNLIGHT FOR HEALTHY BONES

But ultraviolet light – UVB – can also be extremely dangerous. Too much exposure to sunlight will cause skin cancer, as the light produces molecules that directly damage DNA. Here is the great paradox of sunlight – too much of it will burn and can kill – but get the dose right and it is not only curative, but essential for healthy living. Sunlight is needed to produce vitamin D in the skin, and vitamin D is needed to produce healthy bones. Without it, you will develop rickets, a skeletal deformity that is characterized by bowed legs. 

Typical presentation of 2 children with rickets. The child in the middle is normal; the children on both sides have severe muscle weakness and bone deformities, including bowed legs (right) and knock knees (left). From Holick M. Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease. Am J Clin Nutr 2004;80(suppl):1678S–88S.

SUNLIGHT FOR A HEALTHY IMMUNE SYSTEM

The sun’s light has been shown to have effect the immune system, although many of these effects are only poorly understood. 

When some nerve fibres are exposed to sunlight, they release a chemical called neuropeptide substance P. This chemical seems to produce local immune suppression.  Exposure to the ultraviolet wavelengths in sunlight can change the regulation of T cells in the body which can also modulate autoimmune diseases.

SUNLIGHT TO TREAT MELANOMA?

While sunlight can cause skin cancer, it has been shown to release a hormone called alpha melanocyte-stimulating hormone. This hormone appears to limit the damage to DNA damage from sunlight and so may actually reduce the risk of melanoma (but don't try this as a treatment yet. It's certainly not ready for prime time.)

SUNLIGHT FOR YOUR MOOD

Then there’s sunlight for your mood. Seasonal affective disorder – SAD – is caused by a lack of exposure to sunlight, which most affects those living in the northern latitudes in the winter.  SAD was first described in 1984 by Norman Rosenthal working at the National Institute of Mental Health but why it happens is still something of a mystery.  Rosenthal went on to write several best selling books on SAD and how to beat it. The answer appears to be something to do with sitting in front of a lamp that mimics sunlight (but the evidence that this works is still controversial).

 SUNLIGHT FOR BABIES WITH JAUNDICE

Sunlight is also a great treatment for babies with neonatal jaundice. This condition is very common and is caused when the baby breaks down the fetal hemoglobin with which it was born. A product of that breakdown is bilirubin, and if this is allowed to build up in the tissues it can cause lethargy, difficultly feeding, and in rare and extreme cases, brain damage. However, sunlight (or more precisely, the blue band of the spectrum at 459nm)  breaks down this dangerous bilirubin molecule into a harmless one called biliverdin.  So the best treatment for a newborn baby with mild jaundice is to put them out in the sun.  (Failing that, or if the degree of jaundice is not mild, you can consider phototherapy in the hospital.) 

The absorbance spectrum of bilirubin bound to human serum albumin (white line) is shown superimposed on the spectrum of visible light. Clearly, blue light is most effective for phototherapy, but because the transmittance of skin increases with increasing wavelength, the best wavelengths to use are probably in the range of 460 to 490 nm. Term and near-term infants should be treated in a bassinet, not an incubator, to allow the light source to be brought to within 10 to 15 cm of the infant (except when halogen or tungsten lights are used), increasing irradiance and efficacy. For intensive phototherapy, an auxiliary light source (fiber-optic pad, light-emitting diode [LED] mattress, or special blue fluorescent tubes) can be placed below the infant or bassinet. If the infant is in an incubator, the light rays should be perpendicular to the surface of the incubator in order to minimize loss of efficacy due to reflectance. From Maisels and McDonagh. Phototherapy for Neonatal Jaundice. New England Journal of Medicine 2008.358;920-928.

SUNLIGHT FOR INFECTIOUS DISEASES

 We don't treat infectious diseases with sunlight any more. But it wasn't always that way. Less than eighty years ago sunlight was recommended as a therapy for some patients with tuberculosis. The authors, writing in the journal Diseases of the Chest were cautious:

Even in those cases where the sun can be of great value, it is in no sense a specific cure for any manifestation of tuberculosis. Rest, good food, and fresh air, are still the fundamentals in treating all forms of the disease; and the sun, where it should be used, is only a valuable adjutant...Heliotherapy is not indicated in all cases of tuberculosis. The majority of patients with this disease should never use it...It is not a sure cure for any type of tuberculosis, but is often, especially in some of the extrapulmonary cases, a very valuable—or even necessary—aid.

In today's daf, Abaye once again noted that the sun can heal. His insight were more correct than he could ever have guessed.  

“Bright light therapy and the broader realm of chronotherapy remain underappreciated and underutilized, despite their empirical support. Efficacy extends beyond seasonal affective disorder and includes nonseasonal depression and sleep disorders, with emerging evidence for a role in treating attention-deficit/hyperactivity disorder, delirium, and dementia.”

— — Schwartz and Olds. The Psychiatry of Light. Harvard Review of Psychiatry 2015. 23 (3); 188.S

[Repost from Nedarim 8.]