82 



assuming that a portion at least of my audience may be but 

 imperfectly acquainted with the main divisions of the brain. 



The encephalon is a collective term, which signifies those 

 parts of the nervous system which are contained in the cranium ; 

 viz., the cerebrum, or brain proper, the cerebellum, and the 

 medulla oblongata. The cerebrum is by far the largest portion 

 of the encephalon, and consists of two lateral halves called 

 hemispheres, each hemisphere being subdivided into three 

 lobes, — anterior, middle, and posterior. The hemispheres pre- 

 sent upon their surface numerous smooth and tortuous emi- 

 nences called convolutions, which have received special names, 

 those only which concern my subject being the frontal convo- 

 lutions, which are known as first, second, and third frontal. 

 Of the cerebellum I need say nothing, — it has no reference to 

 the subject of my remarks. The medulla oblongata is that part 

 of the encephalon which is placed immediately above the spinal 

 cord, forming the bond of union between it and the brain. It 

 is divided into two lateral columns, which are themselves sub- 

 divided into three smaller cords, called the pyramidal, olivary, 

 and restiform bodies. 



The ancients seem to have possessed the most crude notions 

 of the functions of the brain, as evidenced by Hippocrates' 

 assigning the seat of the mind to the left ventricle, and by 

 Aristotle also placing the sensorium commune in the heart. 

 In later times the brain has been universally considered to be 

 the organ of thought and intelligence ; but opinions have been, 

 and are still, divided as to whether it is to be regarded as a 

 single organ, or as consisting of a series of distinct organs, each 

 endowed with a special and independent function ; whether, in 

 fact, the phenomena of intelligence are due to an action of the 

 brain as a whole, or whether the different psychological ele- 

 ments which constitute them ar^ connected with isolated and 

 circumscribed parts of the encephalon. Out of this last theory 

 has arisen the principle of the localization of the cerebral facul- 

 ties, which was, in the early part of the 19th century, announced 

 in a definite form by Gall, who divided the brain into organs 

 endowed with primordial faculties, distinct the one from the 

 other. Gall was the first to attempt to connect the seat of 

 language with any definite portion of the cerebro-spinal centre, 

 by asserting that there was a special organ for language, which, 

 according to him, was placed in those convolutions of the ante- 

 rior lobes of the brain, which rest upon the posterior part of 

 the supra-orbital plates, or, in other words, upon the roof of 

 the orbit. 



This is not the time or place to make more than a passing 



