344 THE BIOLOGICAL SCIENCES AND MEDICINE. [LECT. 



remain healthy ; and this is what happens in most 

 cases (I.e. 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 sim- 

 plest and the lowest forms of animated beings, con- 

 firmed the great induction of the cell theory. Thus 

 the apparently 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 

 explicable by the known laws of matter and motion, 

 is unquestionably largely true. But it is also true, 

 that the living body is a synthesis of innumerable 

 physiological elements, each of which may nearly be 

 described, in Wolff's words, as a fluid possessed of 

 a "vis essentialis," and a " solidescibilitas " ; or, in 

 modern phrase, as protoplasm susceptible of structural 

 metamorphosis and functional metabolism : and that 

 the only machinery, in the precise sense in which the 

 Cartesian school understood mechanism, is, that which 

 co-ordinates and regulates these physiological units 

 into an organic whole. 



In fact, the body is a machine of the nature of an 



