342 THE BIOLOGICAL SCIENCES AND MEDICINE. 



indirectly, their influence was perhaps even more re- 

 markable. 



But, though Harvey made this signal and perenni- 

 ally important contribution to the physiology of the 

 moderns, his general conception of vital processes was 

 essentially identical with that of the ancients; and, in 

 the " Exercitationes de generatione," and notably in the 

 singular chapter " De calido innato," he shows himself 

 a true son of Galen and of Aristotle. 



For Harvey, the blood possesses powers superior to 

 those of the elements ; it is the seat of a soul which is 

 not only vegetative, but also sensitive and motor. The 

 blood maintains and fashions all parts of the body, " id- 

 que summa cum providentia et intellect!! in finem cer- 

 tum agens, quasi ratiocinio quodam uteretur." 



Here is the doctrine of the " pneuma," the product 

 of the philosophical mould into which the animism of 

 primitive men ran in Greece, in full force. !Nor did its 

 strength abate for long after Harvey's time. The same 

 ingrained tendency of the human mind to suppose that 

 a process is explained when it is ascribed to a power of 

 which nothing is known except that it is the hypothetical 

 agent of the process, gave rise, in the next century, to 

 the animism of Stahl; and, later, to the doctrine of a 

 vital principle, that " asylum ignorantiae " of physiolo- 

 gists, which has so easily accounted for everything and 

 explained nothing, down to our own times. 



ISTow the essence of modem, as contrasted with" an- 

 cient, physiological science appears to me to lie in its 



