xm.] THE BIOLOGICAL SCIENCES AND MEDICINE. 343 



too much to say that one half of a modern text-book 

 of physiology consists of applied physics and chemistry; 

 and that it is exactly in the exploration of the pheno- 

 mena of sensibility and contractility that physics and 

 chemistry have exerted the most potent influence. 



Nevertheless, Bichat rendered a solid service to 

 physiological progress by insisting upon the fact that 

 what we call life, in one of the higher animals, is not 

 an indivisible unitary archseus dominating, from its 

 central seat, the parts of the organism, but a com- 

 pound result of the synthesis of the separate lives of 

 those parts. 



" All animals," says he, " are assemblages of dif- 

 ferent organs, each of which performs its function and 

 concurs, after its fashion, in the preservation of the 

 whole. They are so many special machines in the 

 general machine which constitutes the individual. 

 But each of these special machines is itself com- 

 pounded of many tissues of very different natures, 

 which in truth constitute the elements of those organs " 

 (I.e. Ixxix.) " The conception of a proper vitality is 

 applicable only to these simple tissues, and not to the 

 organs themselves " (I.e. Ixxxiv.) 



And Bichat proceeds to make the obvious applica- 

 tion of this doctrine of synthetic life, if I may so call 

 it, to pathology. Since diseases are only alterations 

 of vital properties, and the properties of each tissue 

 are distinct" from those of the rest, it is evident that 

 the diseases of each tissue must be different from those 

 of the rest. Therefore, in any organ composed of 

 different tissues, one may be diseased and the other 



