Absorption. 183 



bloodvessels, after undergoing a change in the intestinal 

 wall which we shall presently indicate. It is said that no 

 sugar, or but very little, is taken up by the lacteals from the 

 bowels, the bulk of the carbo-hydrates being carried off by 

 the portal vein to the liver ; but Colin states that sugar is 

 found in the chyle of the horse, - 12 to -14 per cent, and 

 that this amount is increased by the introduction of glucose 

 into the bowels. 



The gases in chyle are much the same as in lymph, viz., 

 a considerable quantity of carbonic acid, a little nitrogen, 

 and a mere trace of oxygen. 



The composition of chyle varies with the nature of the 

 food; on a hay diet the fat is small, but when fed with 

 oats the amount of fat increases considerably. I have 

 not been able to obtain chyle from the horse that is not 

 slightly reddish in tint ; its reaction is alkaline, and the 

 specific gravity varies from 1007 to 1022. In starving 

 animals, the chyle is more transparent than when collected 

 after a meal. Colin observes that the chyle of herbivora is 

 yellowish or yellowish-green, very slightly opalescent, and 

 in appearance like turbid milk. He also says that the chyle 

 of starving animals, besides being limpid and transparent, 

 has almost lost its coagulability. 



The chyle while passing upwards through the mesenteric 

 glands has added to it certain formed elements — lymph 

 corpuscles — and now possesses the power of spontaneous 

 clotting. 



The movement of chyle is due to the muscular contraction 

 of the villi forcing the chyle onwards, the valves in the 

 lacteals preventing its return. Intestinal peristalsis may 

 also assist, and the negative pressure in the thoracic duct 

 during inspiration must largely help in aspirating the 

 contents of the chyle vessels upwards. 



Absorption in General. 

 The activity of absorption in the horse has been made 

 known to us by the experiments of Colin. 



Absorption from the Respiratory Passages is remarkably 



