274 DIGESTIVE SYSTEM. 



the fats do not pass through the same organs as the preced- 

 ing substances, and that the chyliferous vessel is especially 

 appointed for their absorption. 



We may, indeed, suppose that the fat contained in the 

 intestine, is absorbed by the cells of the villus (epithelial and 

 plasmatic cells), and that it is excreted by them into the 

 central chyliferous vessel. We have already considered the 

 lymphatic vessels as appointed to collect the deeper resi- 

 duum, the waste produced by the life of the epitheliums 

 (see p. 194). 



The fat does not, however, pass through the lymphatic 

 organs only; it is also found in the blood, although the 

 quantity there is very small. The other matters which have 

 been absorbed are also met with in the chyliferous vessels, 

 but their quantity, compared with that of the fat, is infini- 

 tesimally small. 



Some authors, however, entirely deny that the vessels of 

 the portal circulation have the power of absorbing and 

 carrying off the fat. 1 This is because the fat found in the 

 blood is not in the same state as in the chyle : in mammal's 

 blood the fat is never in a free state, but always saponified ; 

 it is, no doubt, saponified by the choleate of soda, in the bile. 



Most poisonous substances are absorbed by the veins; 

 intoxication taking place so rapidly that the poisons can 

 scarcely be supposed to pass through the lymphatic organs. 



Metals absorbed in the form of metallic salts, accumulate 

 in the liver. This is an important fact, for it shows that the 

 liver retains a large proportion of the alimentary substances 

 for the purpose of modifying them. The albumen is trans- 

 formed, because it comes in contact with the hepatic cells by 

 means of the portal circulation. 



We find, in short, that our knowledge of this interior 

 process of absorption is still very incomplete. We have 

 been occupied in studying these phenomena in reference to 

 the living cells in which absorption takes place, and we have 

 considered the process of absorption as an essential feature 

 of these globules. We have, therefore, paid little attention 

 to the physical theories of absorption, or to experiments made 

 with membranes deprived of life. Experiments of this kind 

 have led to the belief that absorption is simply a phenomenon 

 of osmosis. Thus J. Beclard considers the current of absorp- 



1 See Beclard, " Recherches Expcrimentales sur les Fonctions 

 de la Veine Porte." (Arch. Gener. de Medecine, 1818.) 



