254 INITIATIVE IN EVOLUTION 



during profound sleep, recorded in Nature, Vol. 106, Sept. 2, 1920. 

 Light mechanical stimuli, applied during this state of deep sleep 

 to the internal surface of the pinna, especially close to the meatus, 

 produced first, twitching of the facial muscles on the same side ; 

 second, as this ceased the fore foot was moved irregularly towards 

 the ear, and third, as this ceased a rhythmical scratching action 

 of the hind foot took its place, the rate of which seemed to be 

 exactly the same as that of the scratch-reflex in the dog evoked 

 from stimulation of the flank and back. I had not then, unfor- 

 tunately read more than an abstract of the above paper, but if the 

 full account be followed it will be seen tnat the various " territories " 

 belonging to all the former-reflexes are now known as well as the 

 frontiers of a European Kingdom. All I was able to do with this 

 unusual opportunity of a heavy sleep in a normal young cat was 

 to verify more roughly Professor Sherrington's observations and 

 slightly to extend them in respect of a sleeping animal. 



In the course of these observations on a young cat I examined 

 the various regions of the back and flanks with mechanical stimuli 

 of different degrees of strength. These were applied during sleep 

 and I found that it was more often during a modeiate than a light 

 or deep sleep that the following results were shown — chiefly under 

 the stronger stimuli the tail was raised sharply and swept in a 

 circular way, and this would be repeated according as the stimulus 

 Was applied ; but at the same time there was shown a strong, 

 irregular twitching along the flank, extending forwards to a point 

 near the level of the shoulder. This latter reflex would appear to 

 be a reaction on the part of the panniculus carnosus. Both the 

 reflex of the muscles of the tail and this of the flanks appear to be 

 connected in their origin with movements of parasites in their 

 respective territories. 



In considering the scratch -reflex in the cat a subtle bit of 

 adjustment is found. That coarse and simple scratching of its 

 ear, which we see so often in the cat, must have often astonished 

 us for its vigour and yet its bloodless character. This action is 

 of course a purposeful one, for it goes on when the animal is a\*ake. 

 Here if arywhere this profoundly hedonistic animal shows that 

 for it the laws of comfort are its laws of conduct. It is clear that 

 there may be two processes or conditions involved in its bloodless 

 violence. On the one hand the reflex retractile mechanism of the 

 claws may be kept in abeyance by another reaction which is pre- 

 potent ; on the other, it is a fact that the hind foot in the cat is 

 furnished with claws which are much blunter than those of the 

 fore foot. As far as I have been able to examine cats of different 



