Physiology of Animals. 53 



was the first to realize the dignity of the physiologist's 

 calling, maintaining that the art of medicine 

 must rest on a science of physiology, and 

 that physiology without a secure anatomical ground- 

 work was as a house built upon the sand. It was with 

 these convictions that he so assiduously dissected and 

 experimented on monkeys and swine, the human body 

 being then a forbidden subject. He showed, simply 

 enough, that the arteries contain, not air, but blood; 

 and he recognized what remained obscure to Aristotle 

 the meaning of the brain and nervous system. " He 

 was also the first to point out that the nerves of sensa- 

 tion are distinct from those of motion, and are connected 

 with different parts of the nervous system" (Rutherford). 

 He followed Aristotle in striving after a connected 

 system of physiological interpretation, and explained 

 the functions of the body as due to the co-operation of 

 the animal spirit (n-vevpa, \fsvyiKbv) in the brain and nerves, 

 the vital spirit (irvev^a fomKov) in the heart and absorbed 

 from the air by the lungs, and the natural spirit (irvev^a 

 <wt*c>v) in the liver, &c. He elaborated a pathological 

 doctrine of nine temperaments, which has hardly been 

 improved upon since. His system has only historical 

 interest now, but we must remember that it dominated 

 both theory and practice until the sixteenth century. 



With the revival of learning came a re-awakening of 

 physiological interest, but for many years no real 

 advance was made. A minimum of obser- Mediaeval 

 vation was combined with a plethora of Physiology, 

 speculation. Most characteristic, perhaps, was the 

 tendency to invent explanations of function in terms of 

 animal and vital spirits. 



Rising by force of genius high above his contempo- 

 raries was Philippus Aureolus Theophrastus Paracelsus 

 Bombast, of Hohenheim (1493 (?)-i54i), charlatan and 

 thinker. He seems to have been a fascinating person- 

 ality a traveller, who, as he said, "turned over the 

 leaves of Europe, Asia, and Africa, and in so doing 

 suffered much hardship"; a scholar, who learned alike 

 from sage and gipsy, classic and wizard; a democrat, 

 who said, "Get thee behind me, Greek, Latin, and 



