176 ARISTOTLE'S ANHOMCKOMERIA 



question of the extent of Aristotle's knowledge of what are 

 now called nerves. In that passage he says : " Numbness 

 does not affect any part of the body where there is no vej/^ov."* 

 This statement, at first sight, might seem to be evidence of 

 an important discovery, but it has already been shown how 

 unlikely it is that he ever distinguished nerves from sinews 

 (vBupa.). This distinction was first effected, to some extent, 

 by Erasistratus and Herophilus, and more fully by Eufus 

 Ephesius and Galen. 



Aristotle, giving his own views on the functions of the 

 brain, says that Nature has arranged that it should act in 

 opposition to the heart, which is hot, and so regulate it, and 

 has formed the brain of material which is earthy and watery 

 and therefore adapted to have a cooling effect.! The brain, 

 according to him, exercises a very important function in 

 connection with the heart, and is one of the most important 

 organs of the body ; he says that it is reasonable that the 

 membranes about the brain and the heart should be very 

 strong and stout, because the heart and brain require most 

 protection, since they are the chief regulating powers of 

 life.t That the brain, under the influence of pain, grief, or 

 pleasure, exercises a marked effect on the heart is very well 

 known. Aristotle points this out very clearly, although he 

 does not correctly explain it. He says that the heart is 

 very much influenced by the smallest change in the blood on 

 the outer surface of the brain. § 



The sensory organs which he considered to be more 

 reliable than the others are usually situated in the head, for 

 they are rendered more certain in their action, he says, in 

 consequence of their being supplied with the purest blood ; 

 the effect of the action of hot blood would also be to impair 

 the action of the sensory organs, and the eyes in particular 

 are in the head because, he says in effect, both the brain 

 and the eyes are of the nature of water. || 



Aristotle's views on the functions of the brain, therefore, 

 are not fairly represented by stating that the brain is a 

 cooling means, and still less fairly by stating, as Galen seems 

 to do, 11 that Aristotle considered the brain to be a mere 

 sponge, as it were, saturated with water. On the contrary, 

 he assigned to it very important functions in connection 



- H. A. in. c. 5, s. 4. f P. A. ii. c. 7, G526. 



I Ibid. iii. c. 11, 6736. § Ibid. ii. c. 7, 6536. 



II Ibid. ii. c. 10, 6566 ; De Sens2i, dc, c. 2, 488a. 

 H De Usu Partium, dc, viii. c. 3. 



