1 62 



E. LUCILE MOORE. 



hair brush, reacted in the usual manner by contracting the 

 longitudinal and relaxing the circular and transverse muscles. 

 The effect was rather one of excitement, confined chiefly to the 

 anterior end of the body, which seemed to make coordinated 



TABLE I. 



locomotion difficult. The animals expended their energy in 

 excited movements of the head, and occasionally were unable 

 even to proceed the whole length of the track. When continuous 

 trips were obtained, a decrease in rate was found, as has been 

 noted; but this cannot be entirely due to a decrease in muscular 

 activity, as there is frequently clear evidence of an increased 

 irritability. At other times, however, the excitatory effect was 

 not noted, and the slower rate was really indicative of a slower 

 rhythmic contraction as the animal progressed along the trough. 

 This variability of result, expressed as it is in both cases by a 

 decrease in rate, is difficult to explain; and it may be that an 

 explanation is superfluous, and adrenin is not specific in its 

 influence upon planarian'muscle. It is possible, however, that 

 we are dealing here with a definite action of the extract; and 

 that a more detailed study of the effect upon the three kinds of 

 muscles, and a more accurate determination of the physiological 

 condition of the individuals at the time they are tested may 

 throw more light on the subject. A possible explanation may 

 be found in the duration of the influence of the extract. The 



