ANIMAL AUTOMATISM. 221 



Physiology is, at present, incompetent to say anything 

 positively about the matter, or to go farther than the 

 expression of the high probability, that every molecular 

 change which gives rise to a state of consciousness, leaves 

 a more or less persistent structural modification, through 

 which the same molecular change may be regenerated 

 by other agencies than the cause which first produced it. 



Thus far, the propositions respecting the physiology 

 of the nervous system which are stated by Descartes 

 have simply been more clearly defined, more fully illus- 

 trated, and, for the most part, demonstrated, by modern 

 physiological research. But there remains a doctrine to 

 which Descartes attached great weight, eo that full ac- 

 ceptance of it became a sort of note of a thorough-going 

 Cartesian, but which, nevertheless, is so opposed to 

 ordinary prepossessions that it attained more general 

 notoriety, and gave rise to more discussion, than almost 

 any other Cartesian hypothesis. It is the doctrine, that 

 brute animals are mere machines or automata, devoid not 

 only of reason, but of any kind of consciousness, which is 

 stated briefly in the " Discours do la Methode," and 

 more fully in the " Reponses aux Quatriemes Objec- 

 tions," and in the correspondence with Henry More.* 



The process of reasoning by which Descartes arrived 

 at this startling conclusion is well shown in the following 

 passage of the " Eeponses : "- 



* " Re"ponse de M. Descartes & M. Moms." 1649. " (Euvres," tome x. 

 p. 204. " Mais le plus grand de tous les prejuges que nous ayons retenua 

 de notre enfance, est celui de croire que les bStes pcnsent," etc. 



