Page:Popular Science Monthly Volume 62.djvu/352

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this tendency seems to be a fundamental instinct manifested by even the youngest mammals and is evidently of vital importance for their preservation.

Cat.—The cat on which I am able to report was not in good condition after she became suddenly blind in both eyes, and lived but a few days, or I should have been able to note more fully whether her psychic state had been modified by experience.

When put down on the floor she moved about in a slow and apparently cautious way, and, though plainly perfectly blind, when she came near objects she touched them only slightly. In this the whiskers evidently served a good purpose, as was also observed in the rodents. When one made a noise on the floor as by tramping with the feet, puss invariably moved towards the sound, and so perfectly that by walking about one could cause her to describe complicated figures, from which and other observations I conclude that she had become a mere reflex mechanism worked by the most prominent stimuli of the moment from the external world. When she came to a wall, and especially a corner, she stopped and sometimes lay down—showing that the 'puss in the corner' tendency has a deep foundation, for I am inclined to believe that this animal was not conscious in the true sense of the term. This cat had become blind owing to a hemorrhage into the optic thalamus of the brain and lived but a few days afterwards.

I have not reported any other cases in this paper in which there were brain lesions, the discussion being too complicated for my present purpose. That the cat was guided purely reflexly by sounds was evident from the fact that when one stood on a table and tramped as before, puss underneath the table was soon brought to a standstill just below the source of the sounds. Such a remarkable case of guidance reflexly by the ear I had not seen before, and it proved very instructive to me.

Dog.—Of the blind dogs I have observed I shall refer to but one. He was a cross-bred skye terrier and formed one of a litter kept in a room in the college basement. He became totally blind when between two and three months old. After this he soon changed greatly in disposition; he, like the rats, seemed to revert to a sort of feral condition. He would on the entrance of any one into the room hide, and when approached would bite savagely at the extended hand; in fact, in order to catch him it was necessary to throw a sack or some such object over him. He had gnawed away the legs on which Ms cage stood and to which he was chained for a time.

This dog seemed to be at least equal in intelligence to the other members of the litter, his companions. So far as the objects in the room that had a stable situation were concerned, he was perfectly oriented, but if a new object was laid down he would run against it and