1913] 



Gee: Behavior of Leeches 



279 



position no degree of stimulation was sufficient to cause straight- 

 ening out of the body or progressive movement. The strength 

 of cocaine used in these experiments was 0.08 per cent solution. 

 The table showing duration of response (see table X) and the 

 graph (see fig. 10) indicating the same show very clearly the 

 character of the response. Depression was speedy and practi- 

 cally absolute. All of the animals recovered upon being kept in 

 clean water for several hours. 



Fig. 10. — Influence of cocaine on curve of acti\-ity in the leech. Plotted 

 from average responses of ten leeches. Scale same as in preceding figure. 



5. Chloretone 

 Chloretone was tried and found to be very similar to cocaine 

 in its efEects. The initial period of excited responsiveness was 

 even more marked than in the case of cocaine. The following 

 table (see table XI) very clearly indicates this fact. Complete 

 and rapid depression occurred as the result of the poison and 

 the excessive activity of the animal. With a 0.05 per cent 

 solution of chloretone full relaxation of the muscles was secured 



