ACTION ON ANIMALS 133 



symptoms of incoordination, lies on one side, and finally 

 develops convulsions, with failure of respiration, the heart 

 continuing to beat regularly for some time after the com- 

 plete cessation of respiration. Here also the symptoms are 

 accompanied by a decided fall in the body temperature. 



The results following the intravenous injection of the 

 soluble poison are given in the following table: 



TABLE VI 



Time of cessa- Time of cessa- 



No. of animal. Amount of tion of respira- tion of heart- 

 poison injected tion after beat after 

 intravenously. injection. injection. 



1 ... 10 mg. 4 minutes 7 minutes 



2 ... 10 mg. Recovered 



3 ... 10 mg. 3 minutes 6 minutes 



4 ... 10 mg. Recovered 



5 ... 15 mg. 4 minutes 6 minutes 



6 ... 15 mg. 3 minutes 5 minutes 



7 ... 15 mg. 4 minutes 7 minutes 



8 ... 15 mg. 4 minutes 6 minutes 



9 ... 20 mg. 3 minutes 5 minutes 



10 ... 20 mg. 4 minutes 6 minutes 



11 ... 20 mg. 3 minutes 6 minutes 



12 ... 20 mg. 3 minutes 7 minutes 



From the above table it will be seen that in all cases 

 respiration ceased within four minutes after injection. 

 Indeed, the respiratory embarrassment becomes pronounced 

 immediately following the injection. The animal struggles 

 for breath and there is violent retraction of the sternum. 

 No convulsions are seen following the intravenous injection, 

 this being probably due to the inhibitory influence of the 

 anesthetic which has been used during the preparation of 

 the animal for the operation. The failure of respiration in 

 the absence of convulsions would seem to be conclusive 

 evidence that the cessation of this function is due not to 

 mechanical interference during a convulsive attack, but to 

 a direct paralysis of the respiratory centre itself. Further- 

 more, the fact that the heart continues to beat in a perfectly 

 normal manner for from two to four minutes after respira- 

 tion has entirely ceased, would tend to show that the 



