THE OLD PHRENOLOGY AND THE NEW. 



231 



The latter portion is situated at the back of the head, and forms the 

 hinder part of the brain ; the spinal cord (c), which, as every one 

 knows, runs through the spine (vv), being merely a continuation of 

 the nervous centres of which the brain is the chief. In addition to 

 the cerebrum and 

 cerebellum the brain, 

 it may be noted, 

 consists of several 

 very distinct masses 

 of nervous matter, 

 or "centres," each 

 possessing definite 

 functions of its own. 

 A brain, so far from 

 being a single organ, 

 is in reality a collec- 

 tion of nerve-cen- 

 tres, yet the phreno- 

 logists speak of it as 

 if it consisted of the 

 two parts above 

 noted alone. When 

 the surface of the 

 cerebrum is inspect- 

 ed, it is seen to 

 present a very un- 

 equal appearance, 

 due to the fact that 

 its substance is 

 thrown into a large 

 number of folds or 

 convolutions (see fig. 23), as they are technically named by the ana- 

 tomist. The cerebrum, however, is in reality a double organ, 

 formed of two similar halves or hemispheres, which are separated by 

 a deep central fissure, but which are also connected together below 

 by a broad band of nervous matter known as the corpus callosum. It 

 is this latter band which, in addition apparently to discharging other 

 functions, performs the duty of bringing the halves of the cerebrum into 

 relation with one another, and thus serves to produce identity and 

 correlation of action between its various parts. 



To the nature of the "convolutions" our especial attention must 

 be directed. The brain- substance consists of grey and white nervous 

 matter. The grey matter forms the outermost layer of the brain- 

 substance, and encloses the white; the opposite arrangement being 

 seen, curiously enough, in the spinal cord. Now, one evident purpose 



FIG. 23. SIDE VIEW OF THE BRAIN AND SPINAL CORD. (From 

 Bourgery). A, the cerebrum; B, the cerebellum; M.O., the 

 medulla oblongata ; V, the vertebrae, cut in halves ; C, the spinal 

 cord, and the origin of its nerves. 



