THE LIN^ERINa ADMIRERS OF PHRENOLOGY. 
383 
and that on the cerebrum, while differing one from the other 
in minute structure, differ still more from the grey matter which 
is foimd elsewhere, and the function of which is, as we have 
seen, in a general way, well understood. Also the cerebellum 
and cerebral hemispheres resemble each other in being thrown 
into numerous elevations and depressions, in order to expose a 
larger extent to the vascular membrane on their surface, which 
sends its minute branches into them. These circumstances 
might plead a little for the doctrine that the cerebellum is 
conuected with a psychical faculty, whatever that might be, but 
its totally different source of origin is clearly opposed to such a 
notion ; and we are not left merely to speculate on the subject, 
for both disease in the human subject and experiment on 
animals teach us that when the cerebellum is destroyed, the 
power of combining movements so as to regulate and guide 
them is lost, the limbs being still capable of being moved, but 
walking and handling being impossible. Thus it is certain that 
the function of the cerebellum is totally different from what the 
phrenologists hold it to be. 
Examining the cerebral hemispheres in different animals, and 
proceeding from the lower to the higher forms, a progress in 
development is found, similar to the progress made in em- 
bryonic life. Thus in fishes they are represented by very small 
parts in the fore part of the brain; in birds they have not 
extended sufficiently backwards to be in contact with the cere- 
bellum, and their bulk is due almost entirely to the corpora 
striata ; in rodent animals their surface is smooth ; and, as one 
passes to the higher groups of mammals, more and more com- 
plicated convolutions of the surface are met with ; while in man 
by far the greatest complexity is found. 
Whatever the particular cerebral changes may be which 
accompany and are necessary for thought, there can be no 
question that they occur in the grey matter, and that the white 
matter is only useful by bringing the different parts of the grey 
matter into communication one with another, an end which it 
accomplishes very thoroughly by its complicated commissures 
and countless bundles of fibres taking all directions. Judging, 
then, from comparative anatomy, and even on phrenological 
principles, one would expect that, among men, the greater 
the amount of grey matter of a given quality, the more effec- 
tive would the hemisphere be for the exercise of the mental 
faculties ; and this, there is good reason to consider, is to some 
extent actually the case. But the quantity of grey matter varies 
according to other circumstances besides the size of the skull. 
The vertical depth at any one spot, from the surface of the grey 
matter down to the white, differs in different brains ; and what 
is probably more important is, that the complication of the 
yoT , VIII. — NO. XXXIII. c c 
