1913] 



Gee: Behavior of Leeches 



277 



200 



Fig. 9.- — Influence of nicotine on curve of activity in the leech. Solid line repre- 

 sents response of individual 7, table IX; dotted line, the average of ten specimens. 

 Scale: five spaces on abscissa represent a single stimulation period; one space on 

 ordinate, two seconds' duration of swimming response. 



