THE LYMPHATIC SYSTEM. 319 



stances of the animal fluids. It is, however, poorer in albuminous 

 ingredients than the blood. The following is an analysis, by Lassaigne,* 

 of the fluid obtained from the thoracic duct of the cow : 



COMPOSITION OF THE LYMPH. 



Water 



Fibrine 



Albumen ......... 



Fat 



Sodium chloride 



Sodium carbonate ] 



Sodium phosphate > 



Sodium sulphate ) 



Lime phosphate ........ 



1000.0 



Owing to the presence of fibrinogen, the lymph coagulates like blood, 

 within a few moments after its removal from the lymphatic vessels, 

 forming a gelatinous mass, more or less colorless and transparent, or 

 whitish and opaque, according to the proportion of fatty matter present. 

 After coagulation, it separates into a liquid serum and a solid clot. 



In lymph from the thoracic duct, the clot, within a few moments 

 after coagulation, usually assumes a pinkish color, and on microscopic 

 examination is found to contain a few red blood-globules. Their pres- 

 ence is attributed by some observers (Kolliker, Robin) to the accidental 

 rupture of capillary blood-vessels and consequent introduction of their 

 contents into the lymphatic system ; but their occurrence is so constant 

 that it must be doubted whether they are altogether of accidental origin. 

 The pinkish color is never perceptible in lymph when first drawn from 

 the vessels, but only after it has been a short time exposed to the air. 



The fluid drawn from the thoracic duct, especially in carnivorous 

 animals, varies, both in appearance and constitution, at different times. 

 In the ruminating and graminivorous animals, as the sheep, ox, goat, 

 and horse, it is either opalescent, with a slight amber tinge, or nearly 

 transparent and colorless. In the dog and cat, it is also opaline and 

 amber colored in the intervals of digestion, but soon after feeding 

 becomes of a dense, milky white, and continues to present that appear- 

 ance until digestion and absorption are complete. It then regains its 

 original aspect, and remains opaline until digestion is again in proirr 



This variation is due to the absorption of fatty matters during 

 digestion. The chyle is richer than lymph in nearly all its solid in- 

 gredients, but the principal difference between the two consists in the 

 proportion of fat, which is nearly absent from the transparent or 

 opaline lymph, but abundant in the white and opaque chyle. This 

 is shown in the following analysis, by Rees,f of lymph and chyle, 



* In Colin, Physiologie comparee des Animaux domestiques. Paris, 1856, tome 

 ii., p. 111. 



+ London Medical Gazette. London, 1841, vol. i., p. 547. 



