CHYLE. 335 



considered pretty fully the composition and properties of the lymph as well as the different 

 principles taken up by the lacteal vessels which, with the lymph, form the chyle. Some 

 general considerations, however, remain concerning the composition and properties of 

 the chyle as a distinct fluid. 



In the human subject and in carnivorous animals, the chyle, taken from the lacteals 

 near the intestine, where it is nearly pure, or from the thoracic duct, when it is mixed 

 with lymph, is a white, opaque, milky fluid, of a slightly saline taste, and an odor which 

 is said to resemble that of the semen. The odor is also said to be characteristic of the 

 animal from which the fluid is taken ; although this is not very marked, except on the 

 addition of a concentrated acid, the process employed by Barreul to develop the charac- 

 teristic odor in the fluids from different animals. Bouisson has found that the peculiar 

 odor of the dog was thus developed in fresh chyle taken from the thoracic duct. 



The chyle taken from a fistula into the thoracic duct is frequently of a more or less 

 rosy tint ; and it has been a question whether this be due to a peculiar coloring matter or 

 to the accidental presence of a few red blood-corpuscles. Colin, whose experiments in 

 collecting chyle from living animals have been very numerous and successful, assumes that 

 the red coloration is always due to blood-corpuscles coming from the subclavian vein ; the 

 valve at the orifice of the thoracic duct not being always sufficient to prevent regurgita- 

 tion. He has never found blood in the fluid taken from the mesenteric vessels or the 

 receptaculum chyli, and he states, farthermore, that the chyle from these vessels never 

 becomes colored under the influence of the air or of oxygen. 



The reaction of the chyle is either alkaline or neutral. Dalton noted an alkaline re- 

 action in the chyle of the goat and of the dog ; and a specimen of chyle taken from a 

 criminal immediately after execution, examined by Rees, was neutral. Leuret and Las- 

 saigne obtained the fluid from the receptaculum chyli in a man that had died of cerebral 

 inflammation, and found its reaction to be alkaline. 



The specific gravity of the chyle is always less than that of the blood ; but it is very 

 variable and depends upon the quality of the food and particularly upon the quantity of 

 liquids ingested. Lassaigne found the specific gravity of a specimen of pure chyle taken 

 from the mesenteric lacteals of a bull to be 1013, and the specific gravity of the specimen 

 of human chyle examined by Rees was 1024. 



The differences in the appearance of the chyle in different animals depend chiefly upon 

 the diet. Colin found it excessively milky in the carnivora, especially after fats had been 

 taken in quantity ; while, in dogs that were nourished with articles containing but little 

 fat, its appearance was hardly lactescent. Tiedemann and Gmelin found the chyle almost 

 transparent in herbivora fed with hay or straw. They also observed the fact that the 

 chyle was nearly transparent in dogs fed with liquid albumen, fibrin, gelatine, starch, and 

 gluten ; while it was white in the same animals fed with milk, meat, bones, etc. 



It is impossible to give even an approximative estimate of the entire quantity of pure 

 chyle taken up by the lacteal vessels. When it finds its way into the thoracic duct, it is 

 mingled immediately with all the lymph from the lower extremities ; and the immense 

 quantities of fluid which have been collected from this vessel by Colin and others give 

 no idea of the quantity of chyle absorbed from the intestinal canal. "We cannot, therefore, 

 attempt to give even an approximate estimate of the absolute quantity of chyle ; but it is 

 evident that this is variable, depending upon the nature of the food and the quantity of 

 liquids ingested. 



Like the lymph, the chyle, when removed from the vessels, speedily undergoes coagu- 

 lation. Different specimens of the fluid vary very much as regards the rapidity with 

 which coagulation takes place. The contents of the thoracic duct taken from the inferior 

 animals generally coagulate in a few minutes. The first portion of the fluid collected 

 from the human subject by Dr. Rees (the chyle was collected in this case in two portions) 

 coagulated in an hour. Received into an ordinary glass vessel, the chyle generally sepa- 

 rates more or less completely after coagulation into clot and serum, the density and size 



