Rouse, Respiration in Pigeons. 5 i i 



number of animals, or if the different intensities of the stimulus 

 had been used on the same day. But the latter course would 

 not have given opportunity for observing, at the same time, 

 the influence of repetition. 



It will be seen by Table V (last column) that there was a 

 strong reaction to the first of the five stimulations, a less vigor- 

 ous one to the second, and steadily increasing reponses there- 

 after (8.0, 3.7, 4. I, 5.7, 6.9). It is not surprising that the second 



TABLE V. Effect of Repetition. 



reaction was weaker than the first, since the animals were bet- 

 ter prepared for the second stimulus. That there was an in- 

 creased amount of reaction thereafter is probably to be account- 

 ed for, partially on the basis of summation of stimuli, and par- 

 tially in view of the fact that the short illuminations may have 



