508 ABSOEPTION. 



enabled physiologists to form a better estimate of tlie im- 

 portance of the lymph and chyle. In studying the proper- 

 ties of these fluids, the consideration of the lymph naturally 

 precedes that of the chyle ; as the latter consists simply of 

 lymph, to which certain of the products of digestion have 

 been added during absorption from the alimentary canal. 



Lymph. 



Mode of obtaining Lymph. The old methods of obtaining 

 this fluid are no longer employed. In the inferior animals, 

 recently killed, a few drops may be obtained by pricking the 

 lymphatic glands, or by exposing the right lymphatic trunk 

 or the thoracic duct, and collecting the small quantity of fluid 

 which is discharged when these vessels are punctured. Al- 

 though a notable quantity of chyle can be obtained from the 

 thoracic duct of an animal killed during intestinal absorption, 

 it is difficult to collect even a small quantity of fluid during 

 the intervals of digestion. Yarious occasions have presented 

 themselves for obtaining lymph, possessing more or less of its 

 normal characters, from the human subject during life ; but 

 in many of these instances, as in the observations of Wutzer, 

 Sommerring^l^asse, Marchand and Colberg, and some others, 

 there existed some pathological condition of the lymphatic 

 system, and it cannot be assumed that the liquid thus ob- 

 tained was in a perfectly healthy condition. 



The first successful experiments in which the lymph and 

 chyle were obtained in quantity were made by Colin. This 

 observer, in operating upon large animals, particularly the 

 ruminants, experienced no great difficulty in isolating the 

 thoracic duct near its junction with the subclavian vein, and 

 introducing a metallic tube of sufficient size to allow the free 

 discharge of fluid. 1 These experiments, made upon horses 



1 COLIN, Traite de Physiologie Comparee des Animaux Domestiques, Paris, 

 1856, tome ii., p. 100. 



The idea of establishing a fistula into the thoracic duct did not originate with 

 Colin, although he was the first to perform the experiment successfully. In the 



