Anatomical Observations on the Lungs

is believed The text continues from the previous page's catchword 'appen-'. While the Latin 'appenditur' literally means 'is attached' or 'is weighed,' in this context it completes the thought that the lung's substance is perceived as a collection of membranes. to be a collection of the lightest and thinnest membranes, which, when extended and winding, form almost infinite orbicular and sinuous vesicles These 'vesicles' are what modern medicine calls alveoli—the tiny air sacs where gas exchange occurs., just as we see the cells in honeycombs formed from wax extended into walls. These have such a position and connection that there is an open passage from the trachea The windpipe. into them, and then from one to another, and finally they end in the containing membrane.

The senses demonstrate this in lungs recently removed from animals, in which, when they are swollen with air, almost infinite vesicles swollen with air are observed on the outermost surface through magnifying glasses original: "perspicillis". Malpighi was one of the first scientists to use the newly-invented microscope to study anatomy.. One can observe these same things even in a lung cut through the middle and emptied of air, although they are smaller and less conspicuous; they are discovered more clearly and successfully in a lung that has been inflated and then dried out, because on the outermost surface, protruding little circles emerge, and in any cut part, pits and sinuous offshoots formed by a light, extended membrane are seen.

And so that you may bring a doubting mind to certain faith, you shall remove the lungs from a still-living animal, and by injecting water through a siphon original: "siphone". Here referring to a syringe or tube used for anatomical injection. into the pulmonary artery, you will push out all the blood; and you will wash the pulmonary vessels with the passing water. Immediately you will make the whole substance of the lungs—to which the water reaches and from which the blood is drained—whitish and almost diaphanous original: "diaphanam"; translucent or semi-transparent.. These same lungs—if a light compression is first made so that the water already absorbed is forced out, and then air is injected through the trachea—should be dried until swollen in the shade or the sun. Then, when held up to the light, they not only reveal translucent circles on the outside, but when cut open, they safely display the white mass of vesicles to the eyes.

I have engraved an image of these, both in the internal and external region of the lungs, as best I could, at an increased size, so that I might explain myself more easily in the final plates. In the second of these plates, which I was able to compile with the greatest diligence, those membranous vesicles seem to be formed from the end of the trachea, which, departing into flask-like cavities at its extremity and sides, terminates from these into spaces and unequal vesicles.

Reason seems to bring aid to the weakness of the senses, since the air, which from the trachea...