646 ABSORPTION. 



other hand, chyle from vegetable food is almost always transparent, or 

 nearly so, like ordinary serum. Its coagulum is nearly colourless, and 

 resembles an oyster ; and its surface is not covered with the substance 

 analogous to cream. M. Magendie, 1 too, remarks, that the proportion 

 of the three substances, into which chyle separates when left at rest ; 

 namely, the fatty substance on the surface, the clot, and the serum, 

 varies greatly according to the nature of the food ; that the chyle, 

 proceeding from sugar, for example, has very little fibrin ; whilst that 

 from flesh has more ; and that the fatty matter is extremely abundant 

 when the food contains fat or oil ; whilst scarcely any is found if the 

 food contains no oleaginous matter. Lastly: the attention of Dr. 

 Prout 2 has been directed to the same comparison. He found, on the 

 whole, less difference between the two kinds of chyle than had been 

 noticed by Dr. Marcet. In his experiments, the serum of chyle was ren- 

 dered turbid by heat, and a few flakes of albumen were deposited ; but, 

 when boiled, after admixture with acetic acid, a copious precipitation 

 ensued. To this substance, which thus differs slightly from albumen, 

 Dr. Prout gave the inexpressive name of incipient albumen. The fol- 

 lowing is a comparative analysis, by him, of the chyle of two dogs, one 

 of which was fed on animal, and the other on vegetable substances. 

 The quantity of pure albumen, it will be observed, was much less in 

 the latter case. 



Vegetable Food. Animal Food. 



Water 93-6 89-2 



Fibrin 0-6 0-8 



Incipient albumen 4-6 4'7 



Albumen, with a red colouring matter . . . O4 4-6 



Sugar of milk a trace. 



Oily matter a trace. a trace. 



Saline matters 0-8 0-7 



100-0 100-0 



The difference between the chyle from food of such opposite cha- 

 racter, as indicated by these experiments, is insignificant, and indicative 

 of the great uniformity in the action of the agents of absorption. 

 Researches by Messrs. Macaire and Marcet, 3 tend, indeed, to establish 

 the fact, that both the chyle and the blood of herbivorous and carnivo- 

 rous quadrupeds are identical in their composition, in as far, at least, 

 as regards their ultimate analysis. They found the same proportion of 

 nitrogen in it, whatever kind of food the animal consumed habitually ; 

 and this was the case with the blood, whether of the carnivora or herb- 

 ivora ; but it contained more nitrogen than the chyle. These results 

 are not so singular, now that we know that the animal and vegetable 

 compounds of protein are almost identical in composition. (See page 

 545.) 



All the investigations into the nature of the chyle exhibit the inac- 

 curacy of the view of Roose, 4 that chyle and milk are identical. 



1 Op.citat., p. 174. 



. 2 Annals of Philosophy, xiii. 22, and Bridge-water Treatise, Amer. edit., p. 272, Philad., 

 1834. 



3 Memoir, de la Societe de Physique et de 1'Histoire Naturelle de Geneve, v. 389. 



* Weber's Hildebrandt's Handbuch der Anatomic, i. 102, Braunschweig, 1830. 



