47 



considered, are commonly classified according to 

 the particular end to which more or fewer of 

 these actions are subservient, since they would 

 otherwise be altogether innumerable, and the 

 consideration of them would involve a series of 

 useless repetitions, and present an inextricable 

 chaos, without beginning or end. In this view, 

 therefore, we include, under the head of the 

 function of digestion, all the actions of the seve- 

 ral parts of the intestinal canal and its append- 

 ages, which are instrumental to the assimilation 

 of the food ; under that of the function of circu- 

 lation, all the actions of the heart, blood vessels, 

 and other parts, which are subservient to the 

 propulsion of the blood ; and, under that of the 

 function of respiration, all the actions of the 

 chest and its contents, which minister to the con- 

 version of venous into arterial blood, and many 

 other important ends. It is obvious, therefore, 

 that the number of the functions admitted into 

 any treatise on physiology is almost entirely ar- 

 bitrary each of those just mentioned including 

 perhaps twenty distinct functions of twenty dif- 

 ferent parts ; any one of which might have been 

 selected, if we had been so pleased, and treated 

 of as a separate function. But, if the enumera- 

 tion of the several functions be so indefinite, 

 their arrangement is hardly less so ; and accord- 

 ingly, not only very different heads of functions, 

 but very different arrangements of these heads 

 are to be met with in different authors. By the 

 Father of Medicine the sum of the functions of 



H 



