376 THE HISTORY OF BIOLOGY 



active both as a doctor and as a research-worker until the time of his death, 

 which took place in 1855. 



Magendie' s criticism of contemporary vitalism 

 Even in his earliest writings Magendie appeared as a keen opponent of 

 Bichat's vitalism, and the whole of his subsequent work turns on his insist- 

 ence on the possibility and the necessity of applying to the phenomena of 

 life the laws that hold good in physics and chemistry, and, in connexion 

 therewith, the experimental method that brought these sciences such suc- 

 cess. But he also possessed from the very outset a keen eye for the limitations 

 of that method; he repeatedly declares that it is not possible to explain all 

 life-phenomena merely as physical and chemical processes. The life-mani- 

 festations of the nervous system in particular are called by him "vital" and 

 are excepted from the mode of thought that he applies to other life-processes. 

 These vital phenomena are to his mind inexplicable for the very reason that 

 the physical-chemical principles cannot be applied to them; simply to invent 

 on their account a number of theories of a speculative kind he considers to 

 be harmful; he hopes rather that in future the exact method will be appli- 

 cable also to as much as possible of this field of research, for that method 

 alone, he says, can produce results of lasting value. He would take as the 

 basis of his research the method that was created by Galileo and perfected 

 by Newton — • " to observe and to question nature by means of experiment." 

 Among his predecessors in the biological sphere he names first of all Borelli, 

 whose previously described investigations into the mechanism of animal 

 movements he cites with admiration and pursued still further. He applies 

 the same mechanical idea especially to the respiration and the circulation 

 of the blood, at the same time endeavouring to take as full advantage as 

 possible of the progress made by chemistry during his age. In doing so he 

 came into constant disagreement with Bichat, whose theory of the independ- 

 ent life-manifestations of the various organs he desired to replace as far as 

 possible by purely mechanical processes such as could be confirmed by ex- 

 periment or observation. He considers hypotheses in general to be useless; 

 facts alone have any scientific value and what cannot be explained with their 

 aid must for the time being remain unexplained. This scepticism, which he 

 pursues with absolute consistency, undoubtedly proved a useful counter- 

 balance to the unbridled speculation of preceding periods. True, even his 

 criticism could sometimes lead him astray, as when he accepts Spallanzani's 

 assertion that the spermatozoa play no part in fertilization, and yet doubts 

 von Baer's discovery of the egg in mammals; but on the whole his concep- 

 tion of nature is both sound and keen-sighted. It rests, too, on a broad basis; 

 although it is the vital manifestations of the human body that he studied 

 most carefully, nevertheless he makes constant reference to other animal 

 forms and he supplements his text-book on physiology with a systematic 

 survey of the entire animal kingdom. 



