6 University of California Pnhlications in Anatomy [^^ol. 2 



excitable region of the hemispliere, has in the course of time been 

 settled against the unitarian view (Munk, Exner, Luciani, Bastian, 

 Dejerine, Rothmann, Horsley, Head) in favor of the view of complete 

 separation of the motor and somato-sensory functions and their locali- 

 zation into different, though closely neighboring, cortical regions 

 (with the exception of some of the so-called postural movements — 

 ''Einstellungsbewegimgen" — which have recently been discovered to 

 be initiated in the postcentral cortex ; see Graham Brown, Vogt, 1919, 

 Foerster, 1927). Thus in discussing the above question Holmes 

 (1927) states "that the sensory area lies entirely behind the central 

 fissure," and that it "certainly extends over the whole of the post- 

 central gyrus, over the greater part of the superior parietal lobule, 

 and probably on to the anterior part of the supramarginal gyrus"; 

 equally so, according to Goldstein (1927), the anterior limit of the 

 postcentral granular type of cortex as found by Brodmann and 

 Economo-Koskinas is identical with the anterior limit of the somatic 

 sensory region. The most important zone of that region, according to 

 the dualistic conception, should correspond in the human brain with 

 the posterior lip of the sulcus centralis, although the remainder of the 

 postcentral region and a portion of the parietal region also must 

 have a share in the cortical sensory processes. Physiological investiga- 

 tions (Bartholow, Griinbaum-Sherrington, Mills-Frazier, Vogt, Jolly- 

 Simpson, Gushing, Berger, Lewandowsky-Simons, Leyton-Sherrington, 

 Krause, Valkenburg, Foerster, Mankowski, et al.; see Bechterew, Vogt, 

 Monakow, Bergmark, Ariens Kappers, Graham Brown) and clinical 

 and pathological observations (consult Bergmark, Bolton, Monakow, 

 Pieron, Foerster, Kleist, Graham Brown, Goldstein, Holmes, Wilson, 

 Mills) contributed mainly to this solution of the dispute. With the 

 sole exception of cortical cytoarchitecture and myeloarchitecture 

 (Betz, Campbell, Brodman, Vogt, Economo-Koskinas, et al.), anatomy 

 has played a comparatively negligible role here. Besides being less 

 numerous, anatomical investigations have not been able to give such 

 striking nor apparently such conclusive results as have physiological 

 studies or those in the realm of pathology. Moreover, the scattered 

 anatomical studies, and those few clinical observations, which indi- 

 cated for the somato-sensory area a much more extensive region of the 

 cortex than the narrow strip immediately behind the sulcus centralis, 

 have on the whole been ignored. The anatomical evidence adduced by 

 Probst (1906), Eoussy (1907), E. Sachs (1909) and Wenderowic 

 (1915), to mention only the most important, showed clearly that not 



