298 



THE BEHAVIOUR OF HYLA AUREA TO STRYCHNINE, 



As in the European frog, convulsions were first noted when the 

 dose reached about J of the minimal lethal dose. With Hyla 

 the smallest dose recorded in the experiments as producing spasms 

 was 0*01 mg. per gm. body-weight. The average figure was 

 0*015 mg. per gm. body-weight. As the dose was increased the 

 convulsions appeared sooner after the injection of the alkaloid. 

 Table iii. gives the result of such a series. 



Table iii. 









No. of minutes 



No. 



Weight of frog 



Dose in mg. 



between injection of 



in gm. 



per gm. 



strychnine and the 









onset of spasms. 



1 



19 gm. 



0-01 mg. 



53 min. 



2 



— 



0-02 mg. 



42 min. 



3 



187 gm. 



0-05 mg. 



10 min. 



4 



18-4 gm. 



0-07 mg. 



7 min. 



5 



17'7gm. 



0*08 mg. 



6 min. 



6 



17*4 gm. 



0-09mg. 



6 min. 



7 



16-7 gm. 



0-10 mg. 



A\ min. 



8 



16-4 gm. 



0-11 mg. 



4 min. 



9 



16-2 gm. 



0-12 mg. 



4 min. 



10 



16-1 gm. 



0-16 mg. 



3 min. 



11 



15-6 gm. 



0-18 mg. 



2| min. 



12 



15-0 gm. 



0-20 mg. 



1^ min. 



With a small dose such as 0*01 mg. per gm., the convulsions 

 occurred after 53 minutes. The spasms could be elicited for 30 

 minutes, and the frog then appeared quite recovered. As the 

 dose increased the duration of the period in which spasms might 

 occur was lengthened. In the determination of the period 

 during which a stimulus produced general convulsions, the frogs 

 were stimulated at first every 15 minutes, later every hour. 

 When the dose was increased to 0*05 mg. per gm. body-weight 

 the frog rapidly passed into a condition of complete paralysis. 

 No stimulus, either thermal, mechanical, or electrical, caused any 

 reflex response, though electrical stimuli caused local contractions. 

 This state of paralysis was always preceded by a period of from 

 1 to 5 minutes during which spasms might be reflexly produced. 



