CHYLE. 149 



stage of formation. As it traverses the lymphatic glands, and is 

 elaborated by them, it approximates more and more nearly to the 

 blood itself, till it is at last mingled with the latter from the thoracic 

 and the great right lymphatic ducts. In the lowest animals the 

 blood itself is scarcely a higher development than mere lymph, and 

 in none of the invertebrata do lymphatic vessels exist. In the 

 lowest vertebrata, also, no lymphatic glands are found, but lymph- 

 atic vessels .merely, and the lymph is poured directly from these 

 into the nearest veins. 



II. CHYLE. 



Chyle is the fluid obtained from the lacteals (lymphatics of the 

 small intestine) and the thoracic duct; where it is, however, of 

 course, mixed with lymph. It results from the digestion of certain 

 elements of the food ; and the experiments of Bernard would prove 

 that it is derived from the fatty alone. It differs in appearance with 

 the part of the chyliferous system from which it is obtained, and 

 with the state of the animal as to having been lately fed or not. 

 Indeed, lymph alone exists in the lacteals and thoracic duct during 

 fasting. Chyle also varies in different species of animals. 



Human chyle is generally a milky, opalescent, yellowish white 

 or pale reddish fluid, with a saline and mawkish taste, and an alka- 

 line reaction. It coagulates into a very soft, friable coagulum, in 

 about ten minutes after its removal from the vessels. 



Under the microscope, the chyle shows 1. The liquor chyli; 

 2. The morphological elements. 



1. The liquor chyli (intercellular fluid Lehmann) is very similar 

 to the liquor sanguinis, especially if the former be taken for exa- 

 mination from the thoracic duct. The amount of fibrine in human 

 chyle is not yet precisely ascertained, but it augments while the 

 chyle is passing through the mesenteric glands. Subtracting this 

 element from the liquor chyli, the remainder is called the chyle- 

 serum. This resembles the blood-serum in composition, being, how- 

 ever, poorer in albumen, while it is richer in water, fat, extractive 

 matters, alkalies, and salts especially the chlorides of sodium and 

 potassium. Whether it is, like blood-serum, free from iron; is not 

 yet positively decided. It becomes more turbid and milky if more 

 fat is taken in the food, but not otherwise, whether animal or vege- 

 table food be taken. The fat, however, diminishes while the fluid 

 is passing through the mesenteric glands ; partly, doubtless, from 



