Chullin 87b ~ Talmudic Hematology

חולין פז, ב

אמר רב יהודה אמר שמואל כל מראה אדמומית מכפרין ומכשירין וחייבין בכסוי… ר' אסי מנהרביל אומר בצללתא דדמאי

Rav Yehuda says in the name of Shmuel: All mixtures of blood and water that maintain a reddish and render food susceptible to contracting ritual impurity, and are included in the obligation of covering the bloodhue are considered blood and effect atonement by being presented on the altar…Rabbi Asi of Neharbil says: The statement of Rav Yehuda is referring to the clear part of the blood [ i.e., plasma. If the plasma has a reddish hue due to the blood, it has the status of blood and can render food susceptible to contracting ritual impurity].

In today’s page of talmud we find one of the earliest references to a component of the blood known today as plasma. Here is how Rashi explains what Rav Yehuda was describing:

בצללתא דדמא - באותן מים שהם מן הדם עצמן כשהוא נקרש יש סביבותיו צלול כמים ואם יש

The clear part of the blood: The liquid that is part of the blood itself. When blood clots, it is surrounded by a clear liquid…

It took another couple of thousand years for us to understand the nature of this “clear part of the blood.” Here is what you need to know.

The components of Blood

From here.

Sure, blood looks uniformly red, but if you let it stand (and not clot,) or better yet spin a sample in a centrifuge you will notice that to the naked eye it is made up of several components. At the bottom is a layer of dark red stuff, made up of red blood cells - you know, the ones that carry oxygen from the lungs around the body. On top of that is a thinner, lighter layer, made up of white blood cells that fight infection and platelets that are vital in forming blood clots. This layer is known as the buffy coat, from the word buff meaning yellowish (sort of like a manilla envelope). At the very top is a third layer with a yellowish tinge. We call that plasma, and it is what Rav Yehuda called צללתא דדמא.

What is plasma?

Plasma makes up about 55% of the blood volume, and serves several purposes. It is the medium that transports the red and white blood cells around the body, and it contains the clotting factors that well, make blood clot. Without them things can go badly for a baby boy at his circumcision (a topic we have addressed elsewhere). Plasma also contains immunoglobulins which fight infection, electrolytes, hormones and much else besides. But it cannot give you a better memory, prevent memory loss to serious diseases like dementia, improve Parkinson’s disease, or treat multiple sclerosis, heart disease or post-traumatic stress disorder. These are some of the claims of snake-oil type charlatans like this company. Just two days ago, the FDA issued a press statement alerting consumers and health care providers “that treatments using plasma from young donors have not gone through the rigorous testing that the FDA normally requires in order to confirm the therapeutic benefit of a product and to ensure its safety. As a result, the reported uses of these products should not be assumed to be safe or effective.”

“Simply put, we’re concerned that some patients are being preyed upon by unscrupulous actors touting treatments of plasma from young donors as cures and remedies. ”

— FDA Press Announcement Feb 19, 2019.

(Legitimate) Plasma Donation

In the ER I would give whole blood to a patient who was leaking it out of a stab wound. But sometimes all you need to give is the plasma component. For example, in those with clotting deficiencies, plasma can stop life-threatening bleeds. That’s why it is important to donate whole blood (from which the plasma can be spun off) or just plasma (which takes longer to donate but which can be donated more frequently). If you live in the UK or, like me, lived in the UK in the 1980s, you can’t be a plasma donor, because of the fear of passing on a Creutzfeldt–Jakob like-disease, more commonly known as mad cow disease. In fact the UK imports all its plasma from the United States for this very reason.

For the rest of you who can donate, let the mention of plasma in today’s daf yomi prompt to go and donate some blood or plasma. Tell the medic you are donating in honor of page 87 of the Tractate Chullin. Rav Yehuda would be very proud.

New Essay: Vaccines, Hysteria and Rabbinic Responsibility

How are we to frame our thinking about the current wave of anti-vaccine hysteria that has reached a small but vocal number of Orthodox Jews? How might we learn about a response from our rich Jewish intellectual heritage? Perhaps by turning to a small ​sefer written by a long-forgotten rabbi and published in London over two-hundred and thirty years ago.

To read this essay published in The Lehrhaus, click here.

Chullin 66a ~ Do Swordfish have Scales (and are they Kosher)?

A fish is only kosher if it possesses both fins and scales. What happens if the fish only grows scales when it matures, or if the scales fall off as it is being netted? This is question is discussed in today’s page of Talmud.

Rav Shlomo Machfud, Rav of בד"צ יורה דעה examining a swordfish for evidence of scales, Tiberias 2010.

© 2010 by David Willner for Foundation Stone. All Rights Reserved.

חולין סו, א

תנו רבנן אין לו עכשיו ועתיד לגדל לאחר זמן כגון הסולתנית והעפיץ הרי זה מותר יש לו עכשיו ועתיד להשיר בשעה שעולה מן הים כגון אקונס ואפונס כספתיאס ואכספטיאס ואטונס ה"ז מותר

The Sages taught: If a fish does not currently possess scales but will grow them after a period of time, such as the sultanit and afiyatz fish, it is permitted. Likewise, if it has scales now but will shed them when it is caught and rises from the sea, such as akunas and afuna, ketasfatiyas and akhsaftiyas and otanas fish, it is permitted.

The identity if these species is not certain. The Schottenstein Talmud, for example, leaves these names untranslated. But according to some, the אכספטיאס, the akhsaftiyas, is the swordfish. This is the translation found in the Soncino Talmud, and here is the helpful note from the Koren Talmud:

Is it true?

Let's assume that the identification of the אכספטיאס, the akhsaftiyas as the swordfish is correct. All fish will shed some scales when they are thrashing about in a net or fighting at the end of a line. In this regard the swordfish is no different to any other fish. But at first blush, the suggestion that it would loose all its scales when pulled from the water seems rather unlikely. Thanks to modern science, we can better understand the Beraita's claim. It's not that the swordfish looses its scales when removed from the water; rather, the scales of the adult fish are buried deep in the skin, giving it the appearance of having lost its scales.  

“There is some confusion about whether [swordfish] scales become smaller or are replaced by a single scale type in adults and much confusion about the disappearance of scales altogether”

— Govoni, JJ. West, MA. Zivotofsky, D. Zivotofsky AZ. Bowser PR. Collette BB. Ontogeny of Squamation in Swordfish, Xiphias gladius. Copeia, 2004(2), pp. 391–396.

The swordfish and its "disappearing" scales

Dr. Ari Zivotofsky is a Senior Lecturer in Bar-Ilan's Interdisciplinary Science Program. Aside from arguing cases about the status of Jerusalem in front of the U.S. Supreme Court, he has spent considerable time and energy pondering both the kashrut of the swordfish, and the anatomy of swordfish scales. He was one of several authors who published a study in 2004 with the playful title Ontogeny of Squamation in Swordfish, Xiphias gladius. Their study noted that "scales first appear on the abdomen of larval Xiphias at 6 mm standard length. Thereafter, large scales with a single spine increase in number anteriorly and posteriorly in a row along the abdomen and ventral margin." 

An earlier paper from 1982 noted that swordfish develop two types of scales as larvae and juveniles: large, multi-spined row and rostral scales; and small single-spined scales. As the fish matures from larva to juvenile to adult, its scales persist, but become more buried in the dermis, the skin of the fish. It is not that these scales are receding. Rather, the thickness of the dermis increases. You can see this in the photomicrograph below:

Photomicrographs of the integument and scales of Xiphias gladius. (A) The integument with scale (S), epidermis (Ed), and dermis with stratum spongiosum (SSp), stratum compactum (SCm) of a 22.2 mm larvae (scale bar 63 m). (B) The integument of a 330 cm adult (scale bar 45 m). From Govoni, JJ. et al. Ontogeny of Squamation in Swordfish, Xiphias gladius. Copeia, 2004(2), pp. 391–396.

  Zivotofsky notes that swordfish scales continue to grow and are most certainly not resorbed: 

The confusion in the literature about the presence or absence of scales on adult Xiphias owes to the thickening of the dermis above the scale as larval and juvenile Xiphias grow. The result is that only the tips of the scale spines protrude in adults. Scales are often fractured and abraded when fish are caught and processed by the fishery. The cuticular layer of the integument is also covered with a thick layer of mucus, secreted by a network of mucous canals within the epidermis. This mucus lubricates the integument and renders scale spines less conspicuous.

And so modern biology supports the claim, found in today's daf, that when adult swordfish are caught they appear to be without scales.  

So is the swordfish Kosher?

The presence of tiny scales does not automatically give a fish a kosher status. Biological evidence of tiny or buried scales may, or may not be of consequence in Jewish law. Way back in 1968, Rabbi Moses Tendler of Yeshiva University wrote a polemic in The Jewish Observer, arguing that under no circumstances could the swordfish be considered kosher.  Among the "facts - halachic and scientific" on which he based his opinion was this: "With growth the scales disappear and the larger fish including those sold in the market have no scales." We have seen that this is not the case.  Later, he wrote that "in no place in the Talmud or the responsa literature is there any reference to a deviant: a fish that has scales as a juvenile but not as an adult." This may indeed be so. But as we have seen, the swordfish does not loose its scales. It buries them.

The kosher status of the swordfish is a complex question. It involves anatomy, biology, history, halakhic responsa and local tradition.  If you want to learn more, you can read Rabbi Tendler's 1968 article here. Avi Zivitofsky published a lengthy (53 pages!) and comprehensive history of the question in 2008. He focussed less on the scientific issues and more on the historical and halakhic ones, and you can read it here. Print them both up and enjoy reading them over Shabbat, together with a tasty fish dip. Like herring, or ketasfatiyas.   

Scales of Xiphias gladius. (A) Photograph of the ventral aspect of a pre-served larvae 114 mm long (scale bar 1.5 mm). (B) Photograph of a cleared and stained biopsy of the lateral flank of a 150 mm larvae (scale bar 0.3 mm). (C) Photograph of a cleared and stained biopsy of the lateral flank of a 102 cm juvenile (scale bar 0.6 mm). From Govoni, JJ. et al. Ontogeny of Squamation in Swordfish, Xiphias gladius. Copeia, 2004(2), pp. 391–396.

[Encore post from Avodah Zarah 39a.]

Chullin 62b ~ How do Pigeons Drink?

חולין סב,ב

כל כל העופות פוסלין מי חטאת חוץ מן היונה מפני שמוצצת

All birds disqualify the water of purification, except for the pigeon, because it sips the water from the container and none falls back in from its mouth.

In a brief digression from the rules of shechita, the Talmud digresses into ornithology. If a bird sips water in which ashes of the red heifer have been placed (known as מי חטאת) the water can no longer be used. This applies to all birds except for the pigeon, because it sips the water from the container and presumably none falls back into the water from its mouth.

We are most fortunate that back in 1982 Professor G.A. Zweers from the zoological laboratory at the University of Leiden published what is surely the definitive paper on the topic, Drinking of the Pigeon (Columba Livia L.). Zweers opens his 43 page gem by noting that birds drink in many different ways. “Most of them drink like waterfowl; they walk to or through the water, move their beak open and close their beak several times, take some water, tip head and let the water run down by gravity.” However the way in which pigeons drink had for many years been a source of academic debate, and it was time to clear this up once and for all. So Zweers decided to “formulate a mechanical model for the drinking of pigeons….” and film them merrily drinking using high speed cameras. Now Talmudology readers are the lucky beneficiaries of these herculean efforts.

Using a frame by frame analysis of high speed films and X-ray motion pictures, Zweers figured out that thirsty pigeons use “a double-suction or vacuum-pump model” to drink. Here is how it works:

Consummatory drinking is a series of similar movement cycles, each transporting one dose of water into the oesophagus. The swallowing movement cycle shows five phases:

1, capillary action of the beak tips;

2, lingual suction

3, pharyngeal preparation

4, pharyngeal suction;

and 5, oesophageal collection.

A double build up of an area of low air pressure occurs. As a result of the retraction of the tongue in the mouth (acting as a piston in a cylinder) low air pressure develops in the buccal cavity and water is sucked into the mouth. Secondly, a lower air pressure area develops in the pharynx as a result of a depression of its floor, so that the water in the mouth is given a momentum caudad, by which it is forced over the larynx into the oesophagus.

It’s not only pigeons who suck…

The Talmud rules that other than the pigeon any bird that drinks the waters of purification renders it unusable, because it is only the pigeon that sucks in water through its beak. All other birds drink using different mechanisms, during which time drops of water may fall back into the water, and render it unfit. But this isn’t quite the case. Some parrots like the parakeet (known in the United Kingdom and many parts of the Commonwealth as budgerigar) and the fig parrots also use a sucking mechanism to swallow, though they are native to Oceania and the islands of south-east Asia, so the rabbis of the Talmud could not have known this. The African fork-tailed drongo (Dicrurus adsimilis) sucks in water like pigeons, but then tip their heads back to swallow it. And finally, the common sandgrouse drinks using a very similar mechanism to pigeons.

To conclude: the pigeon is not the only bird that uses suction to drink, but it is certainly one of the few species that do so. We had the benefit of high-speed photography and a determined German professor, but the rabbis of the Talmud had only their daily observations to guide them, and most of the time that was good enought.

“Pigeons and doves are among the few birds that can suck water while their head is down. They don’t need to look skyward to swallow.”

— Bird Watchers Digest