278 University of California Puhlications in Zoology [Vol. 11 



is immediately removed to a dish of clean water two to four 

 hours serve to remove the nicotine sufficiently for the animals 

 to execute slow but co-ordinated movements. There is consid- 

 erable variation in this regard, however, since many of the leeches 

 fail to recover entirely from the effects of the nicotine. 



4. Cocaine 

 With regard to the action of cocaine in invertebrates, Cushny 

 (1910) says: "In some cases, notably in the higher inverte- 

 brates, the final depression is preceded by a stage of increased 

 movement, and it is said that irritability of the nerve is also 

 augmented at first. ' ' This certainly seems to be the case in 

 Dina; for here the activity is at first extremely accentuated, and 

 depression as abrupt. The final effect of the drug seemed to be 

 that of paralysis, the longitudinal muscles often contracting until 

 the body of the animal was very strongly curled. From this 



