Paḥad Yitsḥak (The Fear of Isaac)

Paḥad Yitsḥak, originally consisting of twenty volumes, was printed in part during the author’s lifetime (1750, 1753) and in part after his death. Considered the first halakhic encyclopedia, it is organized alphabetically, offering definitions and explanations of talmudic and rabbinic terms using Isaac Lampronti’s extensive scientific and medical knowledge.

[Rashi ad loc: There are three pipes—“The windpipe splits into three pipes after it enters the chest.”

One leads to the lung—“And it splits inside it, and these are the bronchiae (simponot).”—Ed.]²

And I, the young author, have difficulty with the interpretation of Rashi and those who follow him, for it seems that they think the tube of the lungs is the tube that enters the heart and the liver, and every scholar who knows something in the field of surgery shall see with his own eyes [emphasis added], with a little observation, that this is incorrect. The conclusive proof is that after you cut the liver completely and its artery or its large bronchial tube, and separate it from the lung, and similarly after you cut and separate the entire heart and its large artery from the lung, still the lung will rise with inflation, whereas if the tube of the liver and the tube of the heart split off from the tube of the lung, the air should leave through there when they are separated from the lung, and many very large holes remained there.

And I already showed this matter to great and distinguished rabbis and they conceded the truth of my view, namely that the lung pipe splits off and separates into the bronchiae and tendrils [kenokanot], which enter the lung and do not go out from it at all. These bring air in and out of the lung, and they do not bring blood at all. And we do not care if the lung contains vessels [mizrakim] and arteries, which pump and do not pump, that bring blood rather than air in and out, pulled from the “great pumping vessel” and from the “non-pumping vessel” called cava, which bring blood to the liver from the lung, and from the lung to the heart, and from the heart to the lung and to the entire body. And there is no relation at all between these vessels and between the windpipe [gargeret], bronchiae and lung tendrils, and they do not pour into each other at all. Thus, the tube that splits off to the heart and the liver is neither from the windpipe nor from the lung tendrils, as Rashi thought, but rather from the “great pumping artery” and the “great non-pumping artery.” [ . . . ]

In 5487 [1726/27] the Fellow Shimshon Hayyim Nahman of Modena who lives in Mantua and pours water on the hands of R. David Finzi asked me, on behalf of his teacher and of the entire General Academy of Mantua, to send them these words of mine, so they could examine them and prove empirically [emphasis added] whether or not I am right. I sent these words in a letter and I asked him to ask the Rabbi and his academy to endorse with their signatures whether my words are true. And here is what he answered on July 17, 5487 [1727]: