נדה יט, א
תניא נמי הכי שחור כחרת עמוק מכן טמא דיהה אפי' ככחול טהור ושחור זה לא מתחלתו הוא משחיר אלא כשנעקר הוא משחיר משל לדם מכה לכשנעקר הוא משחיר
It was taught in a baraita: The black color of blood that is impure is blood as black as cheret. If the black is deeper than that, the blood is ritually impure; if the black is lighter than that, even if it is still as dark as blue, the blood is ritually pure. And this black blood does not blacken from its outset, when it is inside the body; rather, it blackens only when it is removed from the body. This is comparable to the blood of a wound, which is initially red, but when it is removed from the body it blackens.
In the discussion over the various kinds of uterine bleeding that render a woman ritually impure, the Talmud pauses to consider the color of the blood itself. Perhaps blood is only considered to be, well, blood, when it is red. Rabbi Abahu thought so, and brought a proof from the Second Book of Kings (3:22):
אמר רבי אבהו דאמר קרא (מלכים ב ג:כב) "ויראו מואב את המים אדומים כדם" למימרא דדם אדום הוא אימא אדום ותו לא
Rabbi Abbahu said that the verse states: “And the sun shone upon the water, and the Moabites saw the water some way off as red as blood” [which indicates that blood is red. The Talmud asks:] Is this to say that blood is red? If so, one can say that only blood that is red like the blood of a wound [is ritually impure], and no more colors of blood are impure.
the many colors of blood
This is not the first time we have encountered talmudic hematology and a discussion of the color of blood. When we studied Chullin (87b) we read the following
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].
That is 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.” 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 “the clear part of the blood” - צללתא דדמא. So that is the plasma.
Today’s page of Talmud does not address the separate color of the plasma, but the combined color of blood that has been left to clot outside of the body.
THE COMPONENTS OF BLOOD
As anyone who has cut their knee will know, the blood that first oozes out is not bright red but a darker hew. This is blood from the venous side of the circulation; there is little oxygen in this blood since it has all been extracted by the muscles and organs that need it. The hemoglobin molecules in the red blood cells shine a different, darker color when they are not carrying a molecule of oxygen. Hence the darker blood.
Hopefully you’ve never done this, but cutting an artery is a whole different story. The blood does not trickle out. It gushes out like a little fountain. And it is bright, bright red. It comes out under force because the arteries are connected directly to the heart and carry the blood under pressure. It is bright red because the hemoglobin has just taken a trip through the lungs where they have happily bound to a molecule of oxygen. And oxyhemoglobin is bright red.
As the Talmud notes, once blood leaves the body it darkens (as oxyhemoglobin and other proteins break down) and turns black. The rabbis ruled that this denatured black blood is as ritually impure as its brighter red former self.
the Sacred as Red
“Red has always connoted blood in all its ambiguous, multivocal meanings “ wrote Melissa Meyer in her 2005 book Thicker Than Water: The origins of blood as symbol and ritual. There are so many examples of this in the rich tradition of Judaism. At a brit, the Jewish circumcision ceremony, the community responds in unison and chants a verse from Ezekiel (16, 6):
“וָאֶעֱבֹר עָלַיִךְ וָאֶרְאֵךְ מִתְבּוֹסֶסֶת בְּדָמָיִךְ וָאֹמַר לָךְ בְּדָמַיִךְ חֲיִי וָאֹמַר לָךְ בְּדָמַיִךְ חֲיִי
– And when I passed by you, and you were weltering in your blood, and I said to you – In your blood you shall live, and I said to you – In your blood you shall live.”
At the brit, blood is life affirming. But when expelled from the uterus, blood symbolizes the missed opportunity for life and transmits ritual impurity. As if to emphasise the multivocal meanings of the color, the most important ritual of purification described in the Torah (Numbers 19) required the ashes of a heffer. And not just any heffer. A red one, known as para adumma (פָרָה אֲדֻמָּה) the red cow.
זֹאת חֻקַּת הַתּוֹרָה אֲשֶׁר־צִוָּה יְה’ לֵאמֹר דַּבֵּר אֶל־בְּנֵי יִשְׂרָאֵל וְיִקְחוּ אֵלֶיךָ פָרָה אֲדֻמָּה תְּמִימָה אֲשֶׁר אֵין־בָּהּ מוּם אֲשֶׁר לֹא־עָלָה עָלֶיהָ עֹל׃ וּנְתַתֶּם אֹתָהּ אֶל־אֶלְעָזָר הַכֹּהֵן וְהוֹצִיא אֹתָהּ אֶל־מִחוּץ לַמַּחֲנֶה וְשָׁחַט אֹתָהּ לְפָנָיו׃ וְלָקַח אֶלְעָזָר הַכֹּהֵן מִדָּמָהּ בְּאֶצְבָּעוֹ וְהִזָּה אֶל־נֹכַח פְּנֵי אֹהֶל־מוֹעֵד מִדָּמָהּ שֶׁבַע פְּעָמִים׃
This is the ritual law that the LORD has commanded: Instruct the Israelite people to bring you a red cow without blemish, in which there is no defect and on which no yoke has been laid. You shall give it to Eleazar the priest. It shall be taken outside the camp and slaughtered in his presence. Eleazar the priest shall take some of its blood with his finger and sprinkle it seven times toward the front of the Tent of Meeting.
In many other cultures, both sacred and taboo objects are colored red. Here is Meyer (p9):
Indians bloodied or reddened sacred statuettes and stones. Sacred trees in Madagascar and Estonia were painted with blood. Greeks tinged Dionysian statues red. Romans touched up Jupiter's face with red colorants prior to festivals. In the Congo and West Africa, some native groups marked the new moon by applying fresh red pigment to sacred statues. The Chukchi daubed sacred tent poles and charms with blood.
Nothing evinced women's fertility more than the color red. Across cultures, many believed that menstrual blood retained in the womb formed a fetus. This most powerful substance was of particular concern when it had obviously not gone to create a child. The Zaramo of Tanzania extensively ritualized mkole tree sap, which turned from white to red, powerfully symbolizing female fertility cues. Fathers gave Nepalese girls red clothing at menarche. Unmarried girls wore red beaded necklaces. Pubescent Navajo girls wore red sashes during their puberty ritual, the kinaalda. Menstruating women often protected their communities by marking themselves red. Women of the Brazilian Tapuya, African Gold Coast, and Kaffir painted their bodies red. Among Victoria tribes, menstruating women were painted red from the waist up. Menstruating Australian Dieri women wore red pigment around their mouths. In India, menstruating women wore blood-stained scarves around their necks."
THe blood of the young and the Failed start-up AMbrosia
The Mishnah on today’s page identified the color of blood as "that which flows from a wound” (איזהו אדום? כדם המכה). On page 19b the Talmud returns to the color of blood:
אמי ורדינאה א"ר אבהו כדם אצבע קטנה של יד שנגפה וחייתה וחזרה ונגפה ולא של כל אדם אלא של בחור שלא נשא אשה ועד כמה עד בן עשרים
The Sage Ami of Vardina says that Rabbi Abbahu says: It is red as the blood that flows from the smallest finger of the hand, which was wounded and later healed and was subsequently wounded again. And this is not referring to the finger of any person, but specifically to the finger of a young man who has not yet married a woman. And furthermore, this does not mean any young man; rather, until what age must he be? Until twenty years old.
Rabbi Abahu who lived in Israel in the third century, declared that there was something special about the blood of a young person - or rather, that of a young unmarried man. It looked different. There is no truth to that declaration: the blood of the young and the blood of the old are identical in color. Even the blood of a person with obstructive pulmonary disease (and hence a slightly lower oxygen content) appears identical to that of a perfectly healthy person; only a machine might tell them apart. Rabbi Abahu wasn’t the only one who believed that certain sources of human blood had special properties. The Roman naturalist and author Pliney the Elder (23-79 CE) lived some two-hundred years before Rav Abahu. He thought it hard to find anything more marvellous than menstrual blood:
On the approach of a woman in this state, must will become sour, seeds which are touched by her become sterile, grafts wither away, garden plants are parched up, and the fruit will fall from the tree beneath which she sits. Her very look, even, will dim the brightness of mirrors, blunt the edge of steel, and take away the polish from ivory. A swarm of bees, if looked upon by her, will die immediately;
For Pliney, menstrual blood could do all manner of things: It kills, animates, and blunts knives all at once. Today you can also find claims that a young person’s blood will heal you (though not that it blunts knives).
In 2016 a startup called Ambrosia offered to sell you a therapeutic blood transfusion from “donors age 16-25.” And the cost of a dose of this young person’s plasma? A mere $8,000. The company’s chief executive is Jesse Karmazin, who graduated medical school but never completed any other medical training. Ambrosia claimed it was running a clinical trial, though it was doing nothing of the sort, and by mid -2017 some 600 people had been gullible enough to part with their $8,000. All of this was a bit much, even for the fairly patient U.S. Food and Drug Administration. In February of this year the FDA issued a statement that shut down the company:
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. Such treatments have no proven clinical benefits for the uses for which these clinics are advertising them and are potentially harmful. There are reports of bad actors charging thousands of dollars for infusions that are unproven and not guided by evidence from adequate and well-controlled trials. The promotion of plasma for these unproven purposes could also discourage patients suffering from serious or intractable illnesses from receiving safe and effective treatments that may be available to them. We strongly urge individuals to consult their treating physicians prior to considering the use of such products for aging indications or for the treatment of conditions such as dementia, Parkinson’s disease, multiple sclerosis, Alzheimer’s disease, heart disease or post-traumatic stress disorder given the known and unknown risks associated with their use
(By the way, in 2016 Karmazin and the Massachusetts Board of Registration in Medicine had reached an agreement: Karmazin voluntarily agreed to cease practicing medicine in the state, and left, apparently for Florida. As others have noted, this tactic is typically used by doctors who are threatened with the loss of their medical license.)
It would of course be a wonderful thing if indeed a young person’s blood could transmit new life and vigor into the old. It does just that, when we transfuse it into those who have anemia, hemophilia or life-threatening blood loss from trauma. It doesn’t kill bees or reverse aging but its life sustaining properties are plentiful. Now go donate some.
[Partial repost from here.]