io6 Journal of Comparative Neurology and Psychology. 



preted as a resultant of two motor responses; first, the activities 

 of locomotion which are set up by the stimulus of the light, and 

 second, the act of jerking back and bending the body from side 

 in response to a strong stimulus from in front. Here are two 

 instincts or reflexes, however we may be pleased to call them, 

 which are in a measure antagonistic in that the first is frequent- 

 ly overcome by the second. The direction of the external stim- 

 ulus determines which of these two instinctive tendencies pre- 

 dominates. We do not need to assume that the animal con- 

 sciously selects and follows up the movements that bring it out 

 of a disagreeable situation, and we need not assume that any as- 

 sociation is established between stimulus and reaction, even of 

 the most fleeting sort. I do not wish to state dogmatically that 

 such an association is never formed in these organisms, since 

 observations on other forms lead me to speak guardedly on this 

 point; but it cannot, I believe, be more than a minor factor in 

 their phototactic response, if it exists, In so far as the effect 

 of previous experience is not involved, the type of reaction in 

 question differs from the trial and error method of primitive an- 

 imal intelligence. At the same time, it resembles that method 

 in that a multitude of movements are made of which only cer- 

 tain ones are followed up. It may be said to be a form of the 

 trial and error method minus the element of learning by exper- 

 ience. 



The type of reaction we have described is one which is 

 very widespread among the lower animals, and it doubtless en- 

 ters as one element into many of the tropic reactions which we 

 commonly explain as the result of forced reflexes. The element 

 of spontaneous, undirected activity is one of vast if not essential 

 importance in the life of nearly all animals. The simpler ani- 

 mals profit by their varied experience, although they may not 

 learn, and thus secure some of the advantages which it is gener- 

 ally considered the special function of intelligence to confer. 



In a valuable paper which appeared after the preceding 

 portion of this article was written Dr. Jennings' points out the 



'Jennings, H. S. Contributions to the Study of the Behavior of Lower Or- 

 ganisms, Washington, 1904. 



