366 FUNCTIONS OF THE NERVOUS SYSTEM, [ch. i. 



rational, seated in the brain. In this doctrine he was followed 

 by Galen, Vesalius, Fernelius, and others, who hence acknow- 

 ledged three spirits : the natural, which pass from the liver with 

 the blood ; the vital, which are carried from the heart to every 

 part of the body through the arteries; and the animal, which 

 are transmitted from the brain through the whole body by 

 means of the nerves. 



SECTION II. THE OPINIONS OF GALEN. 



Erasistratus and Herophilus abandoned the doctrine of 

 Aristotle their master, as to the functions of the brain ; the 

 former taught, when young, that the sensory nerves arise from 

 the meninges, and the motor from the cerebrum ; but when 

 old, he taught that both classes of nerves arise from the me- 

 dullary matter of the brain ; that the animal spirit was from 

 the head, the vital from the heart. Herophilus maintained, 

 that the ventricle of the cerebellum, the calamus scriptorius, is 

 the chief of all the ventricles of the brain, and that the nerves 

 of volition spring from the brain and medulla spinalis. The 

 most important doctrines, however, are those laid down by 

 Galen in the books de placitis Hippocratis et Platonis and de 

 usu pari'ium, and which it will be well to notice more in detail. 



In the first place, Galen refutes the doctrines of Aristotle, 

 by showing that the refrigeration assigned to the brain is 

 abundantly effected by the respiration ; that he himself had 

 always found the brain of animals hot to the touch ; and that 

 it must be so, is proved by the numerous blood-vessels dis- 

 tributed over the pia mater and throughout the brain. More- 

 over, in contradiction to the assertion of Aristotle, that all the 

 organs of the senses are not centered in the brain, he shows 

 that nerves are given off to both ears, to both sides of the nose, 

 to both eyes and their motor muscles, and not only four to the 

 tongue, but also nerves to the pharynx, larynx, gullet, and 

 all the viscera, as well as all parts of the face. Consequently 

 he asks, if the brain be only a refrigeratory, of what use are the 

 various parts of the brain, as for example, the choroid bodies, 

 the retiform plexus, the pineal gland, the pelvis, the infundi- 

 bulum, the fornix, the processus vermiformis, the two meninges, 

 their processes to the spinal marrow, and the branches of the 

 nerves? It would have been suflBcient for the purposes of 



