COMPOSITION OF THE CHYLE. 533 



the human subject by Dr. Rees (the chyle was collected in 

 this case in two portions) coagulated in an hour. 1 Received 

 into an ordinary glass vessel, the chyle generally separates 

 more or less completely after coagulation into clot and 

 serum, the density and size of the clot indicating the pro- 

 portion of fibrin. The serum which thus separates is quite 

 variable in quantity, and is never clear. Its milldness does 

 not depend entirely upon the presence of particles of emul- 

 sified fat, and it is not rendered transparent by ether; it 

 contains, in addition to these particles', numerous leucocytes 

 and organic granules. 



Numerous observations have been made with reference 

 to the influence of different kinds of food upon the chyle ; 

 but these have not been followed by any definite results that 

 can be applied to the human subject. It is usual to find the 

 chyle fluid in the lacteals and the thoracic duct for many 

 hours after death ; but it soon coagulates upon exposure to 

 the air. Although the entire lacteal system is sometimes 

 found, in the human subject and in the inferior animals, filled 

 with perfectly opaque coagulated chyle, 2 the fluid does not 

 often coagulate in the vessels. 



Composition of the Chyle. Analyses of the milky fluid 

 taken from the thoracic duct during full digestion by no 

 means represent the composition of pure chyle ; and it is 

 only by collecting the fluid from the mesenteric lacteals, that 

 it can be obtained without a very large admixture of lymph. 

 In the human subject, it is rare even to have an opportunity 

 of taking the fluid from the thoracic duct in cases of sudden 

 death during digestion ; and in most of the inferior animals 

 which have been operated upon, it is difficult to obtain fluid 

 from the small lacteals in quantity sufficient for accurate 



1 REES, On the Chemical Analysis of the Contents of the Thoracic Duct in the 

 Human Subject. Philosophical Transactions, London, 1842, p. 82. 



2 CRTJIKSHANK, TJie Anatomy of the Absorbing Vessels of the Human 

 London, 1790, p. 101. 



