AN EXPERIMENTAL STUDY OF AN UNUSUAL TYPE 

 OF REACTION IN A DOG. 



Ct. van T. HAMILTON, M.D. 



{McLean Hospital, WaverJey, Mass.) 



With Two Figures. 



These experiments were undertaken in the interests of a prob- 

 lem suggested bv such instances of animal behavior as are with 

 difficulty, or not at all, interpretable in terms of instinct or of 

 associative memory, and which mav be ascribed to accident or 

 not, according to the sympathies and viewpoint of the observer. 



The practical difficulties in the way of limiting, regulating and 

 repeating the stimuli that seem to produce unusual adjustments 

 render the always objectionable apparatus necessary to a sufficiently 

 critical investigation of such a problem; but negative conclusions 

 drawn from results obtained by apparatus experiments cannot 

 properly include a denial of the possibility that such animals as 

 habitually solve their problems by the "trial and error" method 

 of reaction (where instinct does not serve) may, under exceptional 

 circumstances, display a type of reaction which stands higher in 

 the scale of modifiability of behavior. Simplicity of an experi- 

 mental situation calls for like simplicity of reaction to it on the 

 part of the animal; and any artificial complication of an already 

 artificial situation is apt not to be in line w^ith his general reactive 

 tendencies. 



It is to be regretted that, owing to the requirements of my 

 method, I was unable to use more than one animal throughout 

 the 600 experiments; but the efficiency of this method, and the 

 suggestiveness of the results obtained by its use will justify, I 

 hope, the report that is to follow. The subject, a bull terrier of 

 mixed breed, was about four months old when he came into my 

 possession. At that time he knew no tricks whatsoever, had never 

 been trained, and was not used to people and houses. Since 

 then he has had no tuition except what has been necessary to over- 



