Such experiments were not condemned in his lifetime: what he saw when he slit the stomach of a newly fed dog made him a very important discovery in the medical world...
(1581 – 1626) Italian anatomist. He explained the function of the chyle vessels. He was born in Cremona. His date of birth is disputed. He died in Milan on April 24, 1626. In some sources, his name is mentioned as Asellio. He received a medical degree from the University of Pavia. After becoming a professor of anatomy and surgery at the same university, he went to Milan and worked as a freelance physician for a while. Between 1612 and 1620 he was appointed chief surgeon to the army. He died on April 24, 1626 (September 9, 1625, according to some sources) in Milan. His work, De Lactibm, which was published in 1627 and consists of 35 chapters, is important as one of the first anatomical works to include colorful drawings, in addition to its scientific value. The two previous books he wrote are lost.
Chyle (from the Greek word chylos, "juice" is a milky bodily fluid consisting of lymph and emulsified fats, or free fatty acids (FFAs). It is formed in the small intestine during digestion of fatty foods, and taken up by lymph vessels specifically known as lacteals. The lipids in the chyle are colloidally suspended in chylomicrons.
Aselli split the abdominal cavity of a dog in front of witnesses on 23 July 1622 to examine the dog's peritoneum movements; White cord-like formations around the small intestines and the peritoneal fold connecting the intestines to the posterior abdominal wall attracted his attention. When he cut one of these nerve-like formations, he saw a white liquid flowing from it. Furthering his studies, he discovered that this substance was a kind of lymphatic fluid carrying fat particles that had been digested in the small intestines, and that digested food was transported to the body in this way.
It was somewhat coincidental that Aselli made this observation because the dog he had ripped open had just been fed. Indeed, the chyle vessels, which Aselli calls "Venae albae et lacteae" (white and milky veins), can be distinguished from other lymphatic vessels only during digestion. The existence of such vessels was also known to Erasistratus and Hippocrates, but it was Aselli who explained their function. Based on his theory that the liver is the center of the vascular system, Galenos suggested that these vessels also open to the liver. In the second half of the 17th century, Pecquct revealed that the chyle system opened into a sac in the thoracic cavity.
What is Chylis?
Chylis is milky, fat-emulsion-containing lymph, that is, white blood. It is formed in the small intestine by the digestion of dietary fats, and from there it is taken to the lymph system through the lacteal channels. On the other hand, other digested nutrients are taken into the circulatory system through the veins.