ABSORPTION OF THE NUTRIMENT. 9 



of the sweetbread, are mingled with its contents, and produce 

 effects of the most essential kind. The digesting mass, passing 

 onwards from the duodenum, is now ready to afford its nutri- 

 tive essence for absorption into the real interior of the system, 

 a process which takes place chiefly in the two succeeding por- 

 tions of the small intestines, respectively named the jejunum 

 and ilium. The process of absorption in these portions of the 

 intestine is twofold one, by certain minute, short, thread-like 

 bodies hanging into the intestines, termed villi, through which 

 the absorbed matter is conveyed to what is named the lacteal 

 system, and finally into the blood the other, as it would seem, 

 by a direct entrance of such products as are soluble into the 

 veins of those parts of the intestines, so as to become at once 

 mingled with their venous blood. That which is absorbed 

 through the villi undergoes changes probably of much conse- 

 quence, and, beginning thenceforth to be called chyle, is trans- 

 mitted through the minute vessels termed lacteals to certain 

 diminutive organs in the mesentery or double serous membrane 

 which supports the small intestines, named the mesenteric 

 glands there it goes through further changes while it finally 

 is conveyed by the trunk in which the lacteal vessels converge, 

 termed the thoracic duct, to veins at the anterior part of the 

 chest, where it is mingled with the venous blood. Thus, by 

 whichever channel the essential nourishment absorbed from 

 the small intestines gets into the real interior of the living 

 system, it is mingled first, not with arterial blood, but with 

 the blood of veins. As the veins of the intestines join in form- 

 ing a peculiar venous trunk termed the portal vein, which is 

 distributed in the liver, whatever nutriment is taken up directly 

 by the veins of the intestines passes through the liver, and 

 there undergoes important changes ; whence the liver must be 

 regarded as having a twofold office in the function of nutri- 

 tion first, as affording a secretion, namely, the bile, which, 



