THE PSYCHIC DEVELOPMENT OF YOUNG ANIMALS 153 



edges. These processes take a few days for completion, 

 even after there is an obvious opening between the 

 lids ; and it is very doubtful if the animal sees at all) 

 in the proper sense of the word, until the lids are 

 completely separated, if even then ; so that the eyes 

 being open is in itself no guarantee that the animal 

 sees, or, at all events, more than light and shadows. 



The slowness of reflex winking to appear in puppies 

 is surprising, the more so as mature dogs wink very 

 readily when any object is brought near, or moved 

 before the eye. 



Quite otherwise is it with mature birds, and it is 

 almost impossible to get the young to wink, even on 

 touching the lids in some cases I have found. 



In this, and a former litter of St Bernards, the eyes 

 began to open on the llth day, and in a litter of 

 Bedlington terriers on the same day, or perhaps a little 

 earlier. One writer states that the eyes of dogs open 

 on the 8th day. I have never seen this, and do not 

 believe it holds for any pure-bred dogs, at all events. 



But individual differences show to the extent of at 

 least twelve hours. 



HEARING. It is very easy to be deceived in this, on 

 account of motor effects resulting from concussion, or 

 from contact of blasts of air with the skin. I think 

 however, my experiments will be deemed conclusive, 

 and the record of the development of this sense very 

 full. 



There comes a time, as I have noted, when the young 

 dog is more affected by sounds than an older one, 

 owing to the less perfect development of his cerebral 

 cortex, which part of the brain is associated with all 

 higher psychic manifestations, with voluntary move- 

 ments, inhibitions, etc. To this the lack of experience 

 is to be added, for till the dog has learned better, noises 

 of all kinds are excitements which may have unpleasant 



