CHAPTER I. 



THE PRINCIPAL OPINIONS OF AUTHORS, REGARDING THE USES AND 

 FUNCTIONS OF THE NERVOUS SYSTEM, CONCISELY STATED. 



SECTION I. THE OPINIONS OF ARISTOTLE. 



It is remarkable how widely Aristotle with many others of the 

 philosophers and stoics have erred in assigning a use for the brain, 

 having described it as an inert viscus, cold and bloodless, an organ 

 sui generis, not to be enumerated amongst other organs of the 

 body, seeing that it is of no use except to cool the heart. He 

 thus explained how the brain might be the refrigeratory of the 

 heart :^ — Inasmuch as vapours arise from the waters and earth, 

 and when they reach the cold middle region of the air are con- 

 densed into water, which, falling upon the earth, cools it ; so 

 also, the hot spirits carried from the heart to the brain with 

 the blood, and there being cooled, are condensed into water, 

 which again descends to the heart for the purpose of cooling it. 

 He placed the seat of the rational soul in the heart, where it 

 can exercise all its functions, and he therefore made the nerves 

 (of the use of which, in sensation and motion, he was not igno- 

 rant) to arise from the heart. This opinion of Aristotle as to 

 the heart being the seat of the soul, appears to be preserved, even 

 to our own days, in the popular modes of expression, as when a 

 man of a good disposition is said to have a good heart, and the 

 writers on moral science speak of '^ the cultivation of the heart.'' 



It would appear, that anteriorly to Aristotle, Hippocrates 

 had formed a more correct opinion as to the functions of the 

 brain, for in his book ^ de Insania/ he observes, that that man 

 is sane whose brain is undisturbed ; although, in another book, 

 ' de Corde,' referred, however, to the spurious works, he places 

 the mind of man in the left ventricle of the heart. Plato, the 

 preceptor of Aristotle, also thought differently, for he recog- 

 nised three distinct faculties of the mind, having three distinct 

 seats : one was the concupiscent, whose seat was in the liver ; 

 the second, the irascible, seated in the heart ; the third, the 



I 



De Animal, partib., lib. ii, cap. vii. 



