76 Journal of Comparative Neurology. 



concerned, are much complicated by the fact that, in the course 

 of the disease, spinal cord symptoms usually appear. 



The new-born child has but few connections of the first 

 centres with the cortex. The optic radiations do not develop 

 until weeks after birth. In spite of this, however, it may be 

 easily proven that the child sees well, but there appears for a 

 time no evidence of comprehension of what is seen, as in the de- 

 corticated dog, nor of the power to practically apply what is 

 seen. These appear only after the development of the optic ra- 

 diation permits the cooperation of the cortex. But a man who 

 in later life loses the occipital lobe of both sides no longer has 

 the capacity to see, like the dog or the child, with the deeper 

 centres. I have the record of a man who suddenly became 

 completely blind. He lived for years without being able to see 

 in the slightest degree. In the autopsy I found bilateral soften- 

 ing of the two occipital lobes, probably as a result of embolism. 



The cortex plays a more important part and becomes more 

 indispensable the higher we ascend in the animal scale. This is 

 the explanation of the divergent results of the experimenters. 

 It is not only possible but very probable that the destruction of 

 the occipital lobes would have a very different effect on vision in 

 the ape than in the dog or rabbit. 



Since we have discovered that the cortex is something 

 which has gradually been added to the rest of the brain in the 

 animal series and that it serves the higher faculties of psychical 

 life, such as intelligence, experience, and reflection, it is not of 

 slight moment to enquire what sensations are localized in the 

 small cortex which first appears in amphibians, or still better, in 

 reptiles. It is only within the last months that I have reached 

 a solution of this problem. It proves that the cortex of these 

 animals is connected by a strong system of fibers almost exclu- 

 sively with the olfactory apparatus. The phylogenetically old- 

 est cortex serves the olfactory sense and has, even thus early, 

 certain peculiarities which permit us to consider it closely re- 

 lated to the Ammonshorn. The conclusion which is self-evi- 

 dently to be drawn is that the first of the higher psychological 

 functions which makes its appearance in the animal kingdom is 



