I6O E. LUCILE MOORE. 



It was difficult to find a means of measuring the influence of 

 the extract upon the musculature. After unsuccessful attempts 

 to record the effect through electrical stimulation, a method of 

 testing muscular activity by means of the rate of locomotion 

 was adopted. A narrow trough, 6.5 cm. long by -3 cm. in width, 

 was made by cementing two ordinary glass slides, side by side, 

 upon a glass plate. Planarians, put into the trough with a little 

 water, readily progressed from one end to the other, usually in 

 the angle formed by the bottom plate and the edge of one slide. 

 A starting place was then marked off; and with a stop-watch 

 the rate of travel was measured. Only continuous non-stop 

 journeys, from the time the head passed the starting point until it 

 reached the end of the trough, were recorded. A large variation 

 was found both in successive rates of the same individual, and 

 in rates of different normal individuals ; but by taking the average 

 of a number of successive rates for each animal, and by using the 

 same ones both before and after treatment with adrenin, it was 

 possible to secure results which seem to be significant. 



The animals were handled as far as possible in the same way in 

 each experiment; and to avoid differences due to the influence of 

 light, the trough was placed on the table in such a position that 

 the animals moved away from the window in a direction parallel 

 with the entering rays of light. Parker and Burnett (6) have 

 shown that planarians have a "tendency to turn away from the 

 course when directed toward the source of light," and this was 

 easily verified, as it was found almost impossible to keep a worm 

 traveling toward the windbw. In eighteen successive trials only 

 once did an individual finish the whole length toward the light 

 without reversing; but in the other direction full trips were 

 readily obtained. 



In testing the effect upon locomotion, the normal rates of the 

 planarians in water were first recorded, then the rates imme- 

 diately after exposure to the influence of adrenin, and finally the 

 rates after recovery in water. In the first series (Table I.) 

 ten individuals were used. Only two rates for each were taken 

 under each of the three conditions; but a comparison of the 

 averages of the twenty rates thus obtained indicates an effective 

 influence of adrenin upon the locomotor activity. The average 



