SECT. II.] OPINIONS OF GALEN. 367 



refrigeration, if the brain had been made Hke a rude and form- 

 less sponge, nor need there have been so much artificial con- 

 struction as is found in the brain. 



Subsequently, when he is about to indicate generally the 

 use of the cerebrum and cerebellum, he observes that the brain 

 is of the same substance as the nerves, but softer, as it neces- 

 sarily should be, inasmuch as it receives all the sensations, per- 

 ceives all the imaginations, and then has to comprehend all the 

 objects of the understanding, for what is soft is more easily 

 changed than what is hard. Since double nerves are necessary, 

 the soft for sensation, the hard for motion, so specially also the 

 brain is double, the anterior being the softer, the posterior the 

 harder, which is also termed parencephalis. These two cerebra 

 are, therefore, separated from each other by nature, because it 

 would not be at all safe, that the soft should be exposed to the 

 contact and pressure of the hard. 



The use of the anterior or superior ventricles, he says, is as 

 follows : Firstly, to receive air through the nostrils, the ethnoid 

 bone, and the mamillary processes, and mixing this with the vital 

 spirit brought into the ventricles through the arteries from the 

 heart, to prepare the animal spirits transmitted from the brain to 

 the nerves for the purposes of motion and sensation. Moreover, 

 that the brain had a double movement : — a diastoHc, by which 

 it receives the air and vital spirit into the ventricles ; and a sys- 

 tolic, by which it distributes the animal spirits to the nerves. 

 Secondly, by the same entrance, sensible objects, and objects of 

 the faculty of smell, are introduced. Thirdly, the excrementa from 

 the bodies contained in the ventricles collect there, the accumu- 

 lation of which excites apoplexy, unless a suitable outlet be pro- 

 vided ; this, however, is double, the one through the meatus of 

 the nostrils, the other through the infundibulum, or pituitary 

 gland, with its two ducts opening into the palate and cavity of 

 the mouth. The superior ventricles are double, in the same 

 way as other parts are ordained to be double by nature, for the 

 purpose, doubtless, that if the one suffers, the other may serve j 

 for this reason, also, the brain is double, and every sensorium is 

 double. He mentions the case of a youth he saw at Smyrna, to 

 prove the usefulness of double ventricles : this youth had one 

 ventricle wounded, and was thought to have escaped death by 

 the help of God, but Galen says that he certainly could only have 

 lived a short time, if he had been wounded in both ventricles. 



