352 THE BIOLOGICAL SCIENCES AND MEDICINE. 



to these simple tissues, and not to the organs them- 

 selves " (I. c. 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 differ- 

 ent tissues, one may be diseased and the other remain 

 healthy ; and this is what happens in most cases (I. c. 

 Ixxxv.) 



In a spirit of true prophecy, Bichat says, " We have 

 arrived at an epoch, in which pathological anatomy 

 should start afresh." For, as the analysis of the organs 

 had led him to the tissues, as the physiological units 

 of the organism ; so, in a succeeding generation, the 

 analysis of the tissues led to the cell as the physio- 

 logical element of the tissues. The contemporaneous 

 study of development brought out the same result; 

 and the zoologists and botanists, exploring the simplest 

 and the lowest forms of animated beings, confirmed the 

 great induction of the cell theory. Thus the appar- 

 ently opposed views, which have been battling with 

 one another ever since the middle of the last century, 

 have proved to be each half the truth. 



The proposition of Descartes that the body of a 

 living man is a machine, the actions of which are ex- 

 plicable by the known laws of matter and motion, is 



