BY H. G. CHAPMAN. 303 



Summary. — The minimal lethal dose of strychnine for Hyla 

 aurea is 01 mg. per gm. body- weight. The lethal dose is some- 

 what higher in those frogs gathered in winter than in those 

 gathered in summer. The lethal dose is unaffected by the sex of 

 the frog. 



The receptive substance of the muscles of Hyla aurea is 

 sensitive to strychnine, so that the frogs show with appropriate 

 doses typical curare-paralysis. The prominence of this action 

 produces a characteristic type of poisoning in Hyla. 



In conclusion I would express my thanks to Professor Anderson 

 Stuart in whose laboratory this research was undertaken. 



