22 STUDIES ON THE CENTRAL NERVOUS SYSTEM 



of the macula in the calcarine cortex have varied; lately 

 it has been generally assumed that its position is in the 

 occipital pole. In 1917 I advanced arguments showing that 

 it was impossible to accept the idea that the macula is 

 locaUsed exclusively here; in a case of hemianopia duplex 

 caused by a lesion in both occipital lobes central vision was 

 possible notwithstanding the fact that the occipital pole was 

 severed from the central optic radiations. This case does not 

 prove that the macular fibres do not terminate in the cortex 

 of the occipital pole, but it proves that not all of them end 

 here. In 1918 Gordon Holmes advanced the possibility- — 

 after having studied many war cases- — that macular vision, 

 being very highly specialised, has a relatively much more 

 extensive cortical distribution than peripheral vision has. 

 Holmes's suggestion approximates to von Monakow's 

 theory. It may be also in agreement with our observations 

 in monkeys. 



I made several lesions in the cortical optic centres of 

 rabbits. Dr. Putnam of Boston studied in my laboratory 

 the retrograde degenerations in the external geniculate body 

 and has discovered several interesting results regarding the 

 projection of the various quadrants of the retina on the 

 occipital lobe, which he will publish soon. Such lesions have 

 also been recently made in my laboratory in the calcarine 

 cortex of several monkeys. In this way we shall be able to 

 determine the projection of the different parts of the retina 

 and also of the macula in the second optic neuron, because 

 we now know the relations in the primary optic neuron. 

 Both types of degenerations will here meet one another in the 

 external geniculate body. 



One point, however, needs to be emphasized. In our 

 investigations we also took account of the third dimension, 

 as you have seen in my drawings. Up to now workers 

 have always spoken of a localization dorsal and ventral, 

 lateral and medial. It will also be necessary to determine 

 a localization oral-caudal. Our feeling is, that this localiza- 



