864 BIOLOGICAL SCIENCES AND MEDICINE xr? 



Cartesian physiology as a complete expression of 

 vital phenomena. 



For Wolff, the physical basis of life is a fluid, 

 possessed of a " vis essentialis " and a " solidesci- 

 bilitas," in virtue of which it gives rise to 

 organisation; and, as he points out, this con- 

 clusion strikes at the root of the whole iatro- 

 mechanical system, 



In this country, the great authority of John 

 Hunter exerted a similar influence ; though it 

 must be admitted that the too sibylline utterances 

 which are the outcome of Hunter's struggles to 

 define his conceptions are often susceptible of 

 more than one interpretation. Nevertheless, on 

 some points Hunter is clear enough. For example, 

 he is of opinion that " Spirit is only a property 

 of matter " (" Introduction to Natural History," 

 p. 6), he is prepared to renounce animism, (I.e. p. 

 8), and his conception of life is so completely 

 physical that he thinks of it as something which 

 can exist in a state of combination in the food. 

 " The aliment we take in has in it, in a fixed 

 state, the real life ; and this does not become 

 active until it has got into the lungs ; for there it 

 is freed from its prison " (" Observations on Phy- 

 siology/' p. 113). He also thinks that "It is 

 more in accord with the general principles of the 

 animal machine to suppose that none of its effects 

 are produced from any mechanical principle 

 whatever ; and that every effect is produced from 



