GENERAL PHYSIOLOGY OF THE CEREBRUM. 



183 



tion is found in the work of Fritsch and Hitzig* (1870), in which 

 they exposed and stimulated electrically the cortex cerebri in 

 dogs. They observed that stimulation of certain definite areas, 

 particularly in the sigmoid gyrus, gave distinct and constant 

 movements in the limbs, face, etc. (see Fig. 80). This work 

 was- followed quickly by experiments of a similar kind made 

 by numerous observers, in which the cerebrum was stimulated in 

 various animals and finally in 

 man. In addition, the method 

 of ablation of these areas was 

 employed with subsequent 

 study of the animal in regard 

 to the motor or sensory de- 

 fects resulting therefrom, and 

 the results obtained were 

 further extended by careful 

 autopsies upon human beings 

 in whom paralyses of various 

 kinds and sensory defects were 

 associated with more or less 

 definite lesions of the cerebrum. 

 The first outcome of this work 

 was to lead to an extreme view 

 of localization of function in 

 the brain, in which the differ- 

 ent motor and sensory areas 

 were definitely circumscribed 

 and separated one from the 

 other, making the cerebrum a 

 plurality of organs, to use 

 Gall's term. The more recent 



Fig. 80. To sh9\v the motor areas in the 

 dog's brain as originally determined by 

 Fritsch and Hitzig: s, Sigmoid gyrus; A, center 

 for the neck muscles; -F, center for the ex- 

 tensors and adductors of the forelimb; +, 

 center for the flexors and rotation of fore- 

 limb; #. center for the hind limb; O O, 

 center for the muscles innervated by the 

 facial. 



work has tended to modify 

 these extreme views of local- 

 ization and to emphasize the 

 fact that histologically and 

 physiologically the entire cere- 

 brum is connected so inti- 

 mately, part to part, that, although the different regions mediate 

 different functions, nevertheless an injury or defect in one part 

 may influence to some extent the functional value of all other 

 regions in the organ. The general idea of a localization of func- 

 tion has been established definitely, but the modern view is that 

 the cerebrum is composed of a plurality of organs, not completely 



* Fritsch and Hitzig, " Archiv f. Anatomie und Physiologic und wissen- 

 schaftliche Medizin," 1870, 300. 



