XIV BIOLOGICAL SCIENCES AND MEDICINE 365 



an action in the part; which action is produced 

 by a stimulus upon the part which acts, or upon 

 some other part with which this part sympathises 

 so as to take up the whole action " (1. c. p. 152). 



And Hunter is as clear as Wolff, with whose 

 work he was probably unacquainted, that " what- 

 ever life is, it most certainly does not depend upon 

 structure or organisation " (1. c. p. 114). 



Of course it is impossible that Hunter could 

 have intended to deny the existence of purely 

 mechanical operations in the animal body. But 

 while, with Borelli and Boerhaave, he looked 

 upon absorption, nutrition, and secretion as 

 operations effected by means of the small vessels, 

 he differed from the mechanical physiologists, 

 who regarded these operations as the result of 

 the mechanical properties of the small vessels, 

 such as the size, form, and disposition of their 

 canals and apertures. Hunter, on the contrary, 

 considers them to be the effect of properties of 

 these vessels which are not mechanical but vital. 

 " The vessels," says he, " have more of the polypus 

 in them than any other part of the body," and he 

 talks of the " living and sensitive principles of the 

 arteries," and even of the " dispositions or feelings 

 of the arteries." " When the^ blood is good and 

 genuine the sensations of the arteries, or the 

 dispositions for sensation, are agreeable. ... It 

 is then they dispose of the blood to the best 

 advantage, increasing the growth of the whole^, 



