THE BRAIN. 525 
there is less confidence in the location of the various sensory 
centers than of the motor centers. Most investigators are be- 
lievers in a “motor area” par excellence (for the arm, leg, etc.) 
around the fissure of Rolando. This view is now, so far as 
man is concerned, widely accepted. . 
There is agreement in placing the sensory centers behind 
the above-mentioned motor area, and especially in the occipital 
lobes. The tendency to locate a visual center in this region is 
growing stronger. There is much disagreement as to the other 
sensory centers formerly placed in the angular gyrus and tem- 
poro-sphenoidal lobes. The intellectual faculties have not been 
located in any such sense as Gall and his followers attempted 
to establish. The first two frontal convolutions are those per- 
haps to which localization has as yet been least applied. Chiefly 
on clinical and pathological grounds a center for speech has long 
been located in the third (left) frontal convolution (Broca’s) and 
parts immediately behind it. It has been observed that, when 
disease attacks this area,’speech is interfered with in some way. 
We may say then, generally, that the tendency at the present 
time, both on the part of physiologists and clinical observers, is 
to admit localization to some degree and in some sense. This 
has been the result in part of experiments on the dog and es- 
pecially on the monkey, combined with the‘ discussion of clini- 
cal cases which resulted in death (followed by an autopsy), or 
of others marked by a successful diagnosis and removal of 
lesions or other treatment. In other words, the truth, if it will 
be reached at all, must be reached by the method we have ad- 
vocated throughout this work—the discussion of the results of 
as many different methods as can be brought to bear on this or 
any other subject. Neither the experimental nor the pathologi- 
cal method can settle such complex questions, as we shall en- 
deavor to show when we return to the subject later. 
The Circulation in the Brain.—The brain, being inclosed within 
an air-tight bony case, its circulation is of necessity peculiar. 
Since any undue compression of the encephalon may lead to 
even a fatal stupor, it is clear that there must exist some pro- 
vision to permit of the excess of arterial blood that is required 
for unusual activity of the brain. It is to be borne in mind 
that the fluid within the ventricles is continuous, through the 
foramen of Majendie in the roof of the fourth ventricle, with 
that surrounding the spinal cord (spinal cavity); so that an 
increase in the volume of the encephalon in consequence of an 
afflux of blood might be in some degree compensated by an 
