CHYLE. 643 



ately bought several copies of the work of Aselli, which had only ap- 

 peared the year previously; and distributed them amongst his profes- 

 sional friends. Many experiments were made upon animals, but the 

 great desire of De Peiresc was, that the lacteals should be found in the 

 human body. Through his interest, a malefactor, condemned to death, 

 was given up, a short time before his execution, to the anatomists of 

 Aix; who made him eat copiously; and, an hour and a half after execu- 

 tion, opened the body, in which, to the great satisfaction of De Peiresc, 

 the vessels of Aselli were perceived in the clearest manner. Afterwards, 

 in 1634, John Wesling 1 gave the first graphic representation of them as 

 they exist in the human body; and subsequently pointed out more clearly 

 than his predecessors the thoracic duct and lymphatics. Prior to the 

 discovery of the chyliferous and lymphatic vessels, the veins, which 

 arise in immense numbers from the intestines, and, by their union with 

 other veins, form the vena porta, were esteemed the agents of absorp- 

 tion; and, even at the present day, they are considered, by some physio- 

 logists, to participate with the chyliferous vessels in the function; 

 with what propriety we shall inquire hereafter. 



2. CHYLE. 



The chyle, as it circulates in the chyliferous vessels, has only been 

 submitted to examination in comparatively recent times. It varies in 

 different parts of its course. The best mode of obtaining it is to feed 

 an animal; and, when digestion is in full progress, to strangle it, or 

 divide the spinal marrow beneath the occiput. The thorax must then 

 be opened through its whole length, and a ligature be passed round the 

 aorta, oesophagus, and thoracic duct, as near the neck as possible. If 

 the ribs of the left side be now turned back or broken, the thoracic duct 

 is observed lying against the oesophagus. By detaching the upper 

 part, and cutting into it, the chyle flows out. A small quantity only 

 is thus obtained; but, if the intestinal canal and chyliferous vessels be 

 repeatedly pressed upon, the flow may be sometimes kept up for a quarter 

 of an hour. It is obviously impossible, in this way, to obtain the chyle 

 pure; inasmuch as the lymphatics, from various parts of the body, are 

 constantly pouring their fluid into the thoracic duct. 



From the concurrent testimony of various experimenters, chyle is a 

 liquid of a milky- white appearance; limpid and transparent in herbi- 

 vorous animals, but opaque in the carnivorous; neither viscid nor glu- 

 tinous to the touch; of a consistence, varying somewhat according to 

 the nature of the food; a spermatic smell; sweet taste, not dependent 

 on that of the food; neither acid nor alkaline; and of a specific gravity 

 greater than distilled water, but less than the blood. Magendie, 2 Tiede- 

 mann and Gmelin, 3 and Miiller, 4 however, state it to possess a saline 

 taste ; to be clammy on the tongue ; and sensibly alkaline. Its milky 

 colour is generally supposed to be owing to oily matter which occurs in 

 it in the form of globules of various sizes, from ^gi^th to 20*00^ f 

 an inch in diameter, and which are more abundant in the chyle of man 



1 Syntagm. Anatom., viii. 170. 2 Precis, &c., ii. 172. 



3 Die Verdauung nach Versuchen, i. 353, Heidelb., 1826 : or French translation, by Jourdan, 

 Paris, 1827. 



4 Elements of Physiology, by Baly, p. 258, London, 1838. 



