130 POPULAR SCIENCE MONTHLY. 



It would be out of place here to attempt to indicate the full psycho- 

 logical bearing of these facts. But this much may be affirmed, that 

 ihey put out of court all those who are prepared only to argue against 

 the instinctive perception by the eye of the primary qualities of the 

 external world. When stripped of all superfluous learning, the argu- 

 ment against this and every other alleged case of instinctive knowledge 

 is simply that it is unscientific to assume an instinct when it is possible 

 that the knowledge in question may have been acquired in the ordinary 

 way. But the experiments that have been recounted are evidence that 

 prior to experience chickens behave as if they already possessed an 

 acquaintance with the established order of nature. A hungry chick that 

 never tasted food is able, on seeing a fly or a spider for the first time, 

 to bring into action muscles that were never so exercised before, and 

 to perform a series of delicately adjusted movements that end in the 

 capture of the insect. This I assert as the result of careful observation 

 and experiment; and it cannot be answered but by observation and 

 experiment at least as extensive. It is no doubt common for scientific 

 men to discredit new facts, for no other reason than that they do not 

 fit with theories that have been raised on too narrow foundations; but 

 when they do this they are only geologists, or psychologists — they are 

 not philosophers. 



Before passing to the perceptions of the ear, it may be mentioned 

 that, instead of hooding chickens, which had the advantage of enabling 

 me to make many interesting observations on them when in a state of 

 blindness, I occasionally put a few eggs, when just chipped, into a 

 flannel bag made for the purpose. In this bag the hatching was com- 

 pleted artificially, and the chickens allowed to remain in the dark 

 from one to three days. When placed in the light they deported them- 

 selves as regards sight in the manner already described. For the purpose 



a few hours, begin, immediately after the covering was removed, and while they 

 still sat nestling together, to pick at each other's beaks and at specks of oat- 

 meal when these were dropped on them, all noise being as far as possible 

 avoided. (2) Each of the twenty chickens made subjects of the experiment 

 described in the text, began to eat without any assistance from the sense of 

 hearing; the greatest possible stillness being maintained and required during 

 the experiment. (3) Chickens picked up food though rendered deaf while yet 

 in the shell. One of these, deprived of both sight and hearing at its birth, was 

 unhooded when three days old, and nine minutes after it vigorously pursued a 

 large blue fly a distance of two feet, pecking at it several times: the bird 

 proved perfectly deaf. Another with its ears similarly closed, was taken from 

 the dark when a day and a half old, and when an experiment was being tried 

 to ascertain whether it was perfectly deaf — which it turned out to be — it began 

 to pick up and swallow small crumbs. What in this case really surprised me 

 was that, the gum employed in closing its ears having also sealed up one of 

 its eyes, it nevertheless picked up crumbs by sight of its one eye almost if not 

 altogether as well as if it had had two. 



