X 



THE FORE-BRAIN 



607 



of the centre of vision corresponding with the macula lutea 

 lies (in the inner or mesial surface of the occipital lobe ; the 

 scheme proposed by- Munk for dogs is not therefore directly 

 applicable to monkeys. These authors did not test the effects 

 of partial destruction of the visual area ; they merely relied on 

 the reactions to electrical excitation, which varied in different 

 parts of the area. 



It must, however, he remembered that electrical stimulation of 

 the angular gyrus, which according to Schafer and Sanger-Brown 

 is not comprised in the visual area, also produces movements of 

 the eye -balls. It should further be added that in 1895, after the 

 publication of Henschen's clinical researches, Panichi repeated 

 the experiments on the macaque monkey in gur laboratory, with 



Ki<;. 303. Maracus brain viewed from above, A, and from below, B. Both occipital lobes and, on 

 the under surface, part of the temporal lobes bad been cut away. (Schafer and Banger-Brown.) 



quite different results from those of Schafer and Sanger-Brown. 

 He not only confirmed the fact that the visual area of monkeys 

 cannot be restricted to the occipital lobes, but his results 

 confute the view that the focus of central vision is seated in the 

 cortex of the calcarine fissure, cuneus, and, generally speaking, of 

 the mesial surface of the occipital lobe. So that the visual area 

 of monkeys has not been finally determined. 



According to Brodrnann, the area striata of the lower apes 

 extends from the calcarine region over almost the whole lower, 

 mesial, and external surface of the occipital lobe. But not even 

 by accepting Minkowski's view that the visual sphere coincides 

 with the area striata is it possible to explain the fact that 

 after the bilateral destruction of the whole occipital lobe the 

 blindness which ensues is not permanent. A fresh series of 

 experiments directed to the solution of this problem is necessary. 



As regards the visual area in man, it may at once be stated on 

 the strength of a large number of clinical cases that the lesions of 



