In the second half of the 17th century, there were further experiments with blood transfusions. The Italian physician Bartolomeo Santinelli doubted their medical value. But he opposed them for another reason too. Here is what he wrote:

“Let it be allowed to cross the boundaries of medicine for a little while, and in order to satisfy abundantly the curious reader, since the unsuitableness of transfusion has already been proved by medical reasons, let it be permitted to confirm that further by monuments of the sacred pages, for thus its repugnance will become known not only to physicians but to all sorts of learned men. . . . Although indeed the prohibition of the use of blood would have in view only that man should not eat it, for which reason it would seem to pertain less to our cause, nonetheless the purpose of that injunction is contrary to today’s transfusion [practice], so that the one who employs it [blood transfusion] would appear to oppose God who extends clemency.”a

Yes, to Santinelli, blood transfusions were against God’s law.