24 COMPENDItTM OF THE VETERINARY ARl. 



posed to absorb the nutritious parts of the food 

 ill its passage through the intestinal canal. 

 Some physiologists suppose, that the mouths 

 of the lacteals have the power of selecting such 

 parts of the food as are tit to be converted into 

 blood, that no previous separation takes place, 

 and that the bile serves, only as a natural pur- 

 gative, constantly stimulating the intestines, 

 thereby keeping up a small degree of motion 

 in them, and promoting the expulsion of the 

 feculent parts of the food. 



It will probably be asked, how it is that the 

 mass of food passes through the intestines, 

 since they are so convoluted that it cannot 

 possibly be effected by the power of gravity ? 

 but if we examine their structure, this phe- 

 nomenon may be readily explained. The in- 

 testines arc composed, in great measure, of 

 muscular fibres, some of which run in a circular^ 

 and others in a loyigitudiiud direction: when 

 the circular fibres contract, the diameter of the 

 canal is diminished ; and when the longitudinal 

 fibres are in action, it becomes shorter ; and, by 

 the combined action of these fibres, the food 

 is gradually propelled through the whole length 

 of the intestinal canal. The motion thus ex- 

 cited may be distinctly seen m an animal re- 



