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To the Most Distinguished and Learned Man

GIOVANNI ALFONSO BORELLI

AT PISA, OF MATHEMATICS

The Most Celebrated Professor

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Among the dissections which I pursue daily with increasing eagerness, chance brought it about that I should examine some things concerning the lungs more carefully—things which, at other times, I seemed to have perceived only as if in a shadow. These findings, whatever they may be, I believe should be communicated to you; for you will be able, with the genius in which you excel and with your geometric eye Malpighi refers to Borelli’s "geometric eye" because Borelli was a leader of the Iatromathematical school, which sought to explain biological functions through the laws of physics and mathematics. in anatomical contemplation—which with a single glance gathers truth or falsehood from the nature of things—to add your own insights to these observations. It will be your task either to direct these discoveries toward a better use, or to confirm my still wavering mind with your word.

The substance of the lungs is commonly considered fleshy, seeing as it is thought to owe its origin to the blood. It is believed to be not unlike the liver or the spleen, and therefore everyone acknowledges that the lung is red in the fetus since it is nourished by blood alone; consequently, they claim that as a fleshy viscus An internal organ. it is endowed with a "hot and moist" temperament This refers to the ancient Galenic system of medicine, which classified organs and illnesses by four qualities: hot, cold, moist, and dry.. However, a more accurate use of the senses and reason seem to show a different nature of its substance; for by diligent investigation I have found that the whole mass of the lungs, which [is formed] by extending vessels