GREEK BIOLOGY AND MEDICINE 



brain, and the distinctions between vessels and 

 nerves, and divided the motor from the sensory 

 nerves, — an immortal achievement. His 

 autopsies extended the knowledge of patho- 

 logical conditions of the internal organs. 



Mechanical views prevailed in his physi- 

 ology, in which Nature's horror vacui played 

 a leading role. For him, the body, com- 

 pounded of atoms, was vivified by warmth 

 from without: his physiology felt the need 

 of some explanatory principle like oxygen. 

 The source of organic energy was two-fold, the 

 blood propelled through the veins, and the 

 pneuma " which is the energy carrier and dom- 

 inates all vital phenomena. Renovation of 

 the pneuma is brought about through respira- 

 tion, whereby air penetrates into the left side 

 of the heart through the pulmonary vein. Thus 

 two varieties of pneuma result, of which one 

 (the vital pneuma) is propelled into the 

 arteries, its function being to regulate vegeta- 

 tive processes throughout the body; whilst the 

 other (soul-pneuma) has the brain as its goal, 

 whence it effects movement and sensation by 

 way of the nervous system " (Neuburger, 

 p. 182). One sees that Erasistratus was kept 

 from recognizing the circulation of the blood 

 [88] 



