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



The animal spirits, he says, are transmitted from the 

 anterior ventricles to the fourth through the opening, now 

 termed the aqueduct of Sylvius. But he afterwards says, 

 [lib. 8, de usu partium,) that the animal spirits are not contained 

 in the ventricles only, but are diffused throughout the whole 

 substance of the cerebrum and cerebellum. 



The use of the fornix, to which also the corpus callosum 

 belongs, is the same, he says, as of the arches of buildings; 

 namely, to support commodiously and safely the whole of the 

 superjacent part of the brain. 



The eminences, termed nates and testes, and the vermiform 

 process of the cerebellum, serve to open and shut the passage 

 by which the animal spirits are transmitted from the anterior 

 ventricles to the posterior ventricle. Some have attributed this 

 function of a janitor to the conarium [pineal gland] also, but 

 erroneously, since it is not a portion of the cerebrum, but 

 merely a gland, and hence, doubtless, the conarium has the 

 same functions as other glands, namely, to support the ramified 

 veins amongst which they are introduced. 



He agrees with Erasistratus in the opinion, that the plexuses 

 and convolutions are larger in man than in other animals, but 

 he does not admit that the intellect of men depends on this, 

 because asses also have a brain much convoluted. 



Although Galen asserts passim, that the function of the 

 nerves consists in transmitting the animal spirits from the 

 brain to the other parts of the body, for the purposes of sen- 

 sation and motion, because parts are deprived of motion and 

 sensation when the nerve is cut, tied, compressed, bruised, or 

 aflPected with scirrhus, still he does not appear to have been 

 quite certain as to the correctness of his doctrine, since he 

 raises some doubts in the seventh book de Placitis Hipp, et 

 Platonis. Firstly, whether the nerves contain animal spirits 

 like the cavities of the brain ? Secondly, whether this 

 spirit is innate in the nerves, and when a limb is to be moved, 

 is excited only when acted upon by the spirit contained in 

 the cerebrum? Thirdly, whether this spirit be innate in the 

 nerves at all, but rather when we seek to move a limb, 

 whether it does not flow from the brain into the nerve? 

 Fourthly, whetlier the matter of the spirits flows into the 

 nerves from the brain in any way ? or is it not rather its force, 

 virtue, or faculty, just as the substance of the sun remaining 



