208 THE VITAL FUNCTIONS. 



taally the purpose of dividing, or grinding into 

 the minutest fragments, all the harder parts of 

 the food, and thus supplying any deficiency 

 of power in the jaws for accomplishing the 

 same object. Thence the aliment, properly 

 prepared, passes into the cavity appropriated for 

 its digestion, which constitutes the true sto- 

 mach.* In the lower part of this organ a pecu- 

 liar fluid secretion is often intermixed with it, 

 which has been supposed to be analogous to the 

 bile of the higher animals. It is prepared by 

 the coats- of slender tubes, termed hepatic 

 vessels, which are often of great length, and 

 sometimes branched or tufted, or beset, like the 

 fibres of a feather, with lateral rows of filaments, 

 and which float loosely in the general cavity of 

 the body, attached only at their termination, 

 where they open into the alimentary canal.t 



* It is often difficult to distinguish the portions of the canal, 

 which correspond in their functions to the stomach, and to the 

 first division of the intestines, or duodenum ; so that different 

 naturalists, according to the views they take of the peculiar office 

 of these. parts, have applied to the same cavity the term of chy- 

 liferous stomach, or of duodenum. See the memoir of Leon 

 Dufour, in the Annales des Sciences Naturelles, ii. 473. 



t The first trace of a secreting structure, corresponding to 

 hepatic vessels, is met with in the Asterias, where the double row 

 of minute lobes attached to the caecal stomachs of those animals, 

 and discharging their fluid into these cavities, are considered by 

 Carus, as performing a similar office. The flocculent tissue 

 which surrounds the intestine of the Holothuria, is probably 

 also an hepatic apparatus. 



