Anatomical Observations on the Lungs

bring original: "ferunt"; continuing from the catchword on the previous page what is circulated by anatomists, for it is established that the blood, which is less diluted by serum The clear fluid of the blood. as it returns from its journey through the whole body, is diverted into the lungs through the middle pulmonary artery. Likewise, the chyle-like material A milky fluid containing fats and lymph, produced during digestion. and Bartholin’s lymph Refers to the lymphatic fluid described by Thomas Bartholin (1616–1680), a contemporary of Malpighi who identified the lymphatic system.—which is the same as the "white" of the blood—pass through the middle thoracic vessels. Since all these substances can only undergo a crude mixing in the right ventricle of the heart, they are propagated further into the attached lungs.

The structure of the lungs is such that it can mix these substances exactly. Indeed, the branches of the vessels creep through the mass of the lungs down to the smallest parts. Thus, the enclosed substances are broken apart in these divisions as they are spread here and there; they are rolled and mixed by the impact of the branching vessels, allowing them to flow together more effectively into a single nature. This process is driven, in a way, by the air wedged into its own passages likely referring to the bronchi or alveoli; as these passages surround the blood vessels on all sides—now emptying, now filling—they are able to thoroughly mix the entire material through the continuous pressure of their cycles. We see something similar every day when flour is pressed into a mass; for to mix it exactly, we pound it frequently with the hand.

We seek evidence for this truth from the "lungs" of fish, which are formed into gills. In these, the gills are composed of many radiating small plates lamellae resting upon one another. The pulmonary vessels run through these with their smallest offshoots, even to the tips of the rays. These are so arranged that they receive water from all sides, which has a greater bulk than air. This water is pressed by the force of the bony operculum The hard bony flap that covers and protects the gills in fish., narrowing the rays so that sufficient mixing and motion are maintained within the extended vessels and fluids. Furthermore, because mucus is continually and very easily scraped away from that area, it is not unreasonable to believe that those things which, in other animals, would exit through the kidneys or through perspiration are excluded by this compression.

We have a further argument in incubated eggs, specifically from the extreme branching of the umbilical vessels into the white and the yolk. These are multiplied into such tiny parts that they outline a formed network. As this network terminates in infinite branches within the humors, or the colliquamentum A historical term for the first liquid part of a developing embryo that appears before the heart and vessels are fully formed., the smallest parts of the blood are mixed with the juice