THE BRAIN. 499 



has in consequence entered upon a new era of development. 

 Tumors thus localized have been removed successfully, and the 

 patients restored to health. As a result of the various kinds of 

 observations and discussions on this subject of late years, the 

 localizationists are willing to admit that the areas of the cortex 

 can not be marked off mathematically — that, in fact, they 

 " overlap." This is in itself an important concession. Again, 

 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 Bolaudo (Fig. 358). 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 convolu- 

 tion (Broca's) and parts immediately behind it. It has been ob- 

 served that when disease attacks this area speech is interfered 

 with in some way. 



We may say then, generally, that the tendency at the pres- 

 ent time, both on the part of physiologists and clinical ob- 

 servers, is to admit localization to some degree and in some 

 sense. This has been the result in part of experiments on the 

 dog and especially on the monkey, combined with the discus- 

 sion of clinical cases which resulted in death (followed by an 

 autopsy), or of others marked by a successful diagnosis and re- 

 moval of lesions or other treatment. In other words, the truth, 

 if it is to be reached at all, must be sought by the plan we 

 have advocated throughout this work — the discussion of the re- 

 sults of as many different methods as can be brought to bear on 

 this or any other subject. Neither the experimental nor the 

 pathological method alone can settle such complex questions. 

 Although localization of function has not been established for 

 the cerebral cortex in the case of those animals with which the 

 practitioner of veterinary medicine has to deal as it has for man 



