Anatomical Observations on the Lungs

...the juice to be brought soon. From these and similar observations, as I have explained to you elsewhere in letters, when I observed the necessary assistance of the lungs in blood-bearing animals—and since these are idle in the fetus—I saw in women a certain mass called the uterine placenta, in which the umbilical vessels finally terminate. Perhaps not incorrectly, I believed this to be the substitute for the lungs. For through it, the extended vessels branch out in a similar fashion, and the white fluid original: "humor albus"; likely referring to maternal nutrients or chyle-like substances sweating from the mother is so precisely mixed with the abundant blood arriving through the umbilical arteries that the newly formed blood is carried back to the heart, and from there throughout the entire body.

From this union of the smallest particles, there follows not only a stable mixture and fluidity in the blood, but also, through the fermentation of the drawn-in matter, a restoration of the blood-mass occurs at the same time; heat emerges, and a greater and greater freedom of the particles is induced. Evidence of this may be found in the colliquation The process of a solid substance turning to liquid; here, the thinning of egg components during development. and swelling seen in both the egg white and the yolk of incubated eggs. This results from the mixture of blood introduced through the umbilical vessels, in whose windings new blood is generated by the help of the driven, fermenting blood, even while the liver is not yet active.

We experience this same movement in ourselves when, shortly after eating, we feel a swelling in the lungs from the incoming nourishment, followed by heat, an increased pulse, and frequent respiration. I personally feel such a tension particularly after eating greens and legumes. From this, as a certain sharp and swelling fluid works its way in, I can predict to myself and those standing by that a stroke of palpitation will soon occur in my heart; once this has happened, that "wandering bite" original: "vagus ille morsus"; likely referring to a sharp, localized sensation or cramp that subsides after the heart reacts. is removed. This fermentation reveals itself more clearly in hectic patients Those suffering from a wasting disease or "hectic fever," often associated with consumption/tuberculosis., where the blood is sharper than is proper. It not only dissolves and melts the parts into which it flows via the arteries, but as the fermentation proceeds further, it induces such freedom and motion in the blood particles that—neglecting their roles in unity and nutrition—countless particles fly outward: invisibly through the skin, and in a visible, copious evacuation through the kidneys, nostrils, and bowels...