INSTINCTS AND HABITS IN CHICKS 13 



concerned. When chicks, without having previously drunk, 

 respond with the drinking reaction to the surface of smooth 

 white note paper, the edge of white glazed kymograph paper, 

 or the edge of a glass dish, all these objects must be supposed 

 to have some quality or qualities, undoubtedly visual, which 

 evoke the drinking reaction. Here are stimuli that call forth a 

 first drinking reaction independently of other instincts. If 

 further evidence were needed to substantiate the conclusion 

 that the instinct is self-dependent, it is found in certain other 

 observations. After the first actual drinking, the drinking 

 response was made to a grain of food, a piece of black leather, 

 a silver ornament, and, in the case of chicks other than those 

 studied in the special experiment, to a line in some dust on a 

 smooth surface, a white spot on the experiment table, the 

 clean surface of black cardboard, and the polished surface of 

 a table. 



Thus the feeding and drinking instincts are more similar 

 than writers have hitherto supposed. In the case of feeding, 

 the fact seems to be that newly hatched chicks respond to a 

 great variety of objects indifferently, and only later come to 

 select those which are food from the rest ; in the case of drinking, 

 the observations show that, if the need be sufficiently urgent, a 

 large variety of objects in like manner elicit the action, and 

 apparently with a like result. The indiscriminate use of reac- 

 tion I of the drinking instinct may bring the appropriate stimulus 

 for reaction 3, without the co-operation of the pecking and 

 imitative activities. The drinking instinct, therefore, does not 

 " have to be supplemented by imitation, accident, intelligence, 

 instruction, etc., in order to act." 



Finally, is still water a sufficient stimulus for the act of drink- 

 ing? I am by no means ready to say it is not. I regret that 

 my experiments are not so complete on this point as they might 

 have been. There is general agreement at present that chicks do 

 not begin to drink in response to this optical stimulus. But de- 

 prive them of water for a sufficient length of time after hatching 

 and perhaps the " sight of still water " will evoke this instinctive 

 reaction. It is not improbable that the effective element or 

 elements in the objects which have been observed to draw forth 

 the reaction are common also to water. 



