606 



DR. THOMAS R. FRASER ON THE ANTAGONISM BETWEEN 



Experiment 298. 

 Experiment 299. 



With an interval of 35 minutes, death occurred. 

 ,, 40 „ death 



It appears, therefore, that successful antagonism occurs when half a grain 

 of sulphate of atropia is administered thirty minutes, or less, before one and 

 a half times the minimum-lethal dose of physostigma but not when the interval 

 is one of thirty-five minutes, or more. 



The next dose of sulphate of atropia with which experiments of this kind 

 were made was one grain and a half (1*5 gr.). The intervals of time that 

 elapsed before the administration of physostigma and the results obtained 

 were the following : — 



Experiment 300-a. — With an interval of 15 minutes, recovery occurred. 

 Experiment 301-a. „ 30 „ recovery 



Experiment 302-a. 

 Experiment 303-a. 

 Experiment 304-a. 

 Experiment 305. 

 Experiment 306. 



40 

 60 

 65 

 70 



80 



recovery 



recovery 



recovery 



death 



death 



Accordingly, the longest interval compatible with the production of success- 

 ful antagonism that may elapse after the administration of one grain and a half 

 of sulphate of atropia, and before that of one and a half times the minimum- 

 lethal dose of physostigma, is one of about sixty-five minutes. 



I have next to describe, in a similarly abridged manner, a number of experi- 

 ments in which the dose of sulphate of atropia was three grains. 



Experiment 307-a — With an interval of 40 minutes, recovery occurred. 



Experiment 308-a. „ 



Experiment 309-a. „ 



Experiment 310-a. „ 



Experiment 311. „ 



Experiment 312. „ 



Experiment 313. „ 



It is shown by these experiments that successful antagonism occurs when a 

 dose of three grains of sulphate of atropia is administered ninety-five minutes 

 (one hour and thirty-five minutes), or at any shorter period, before one and a 

 half times the minimum-lethal dose of physostigma ; but that it does not occur 

 when the period is prolonged to one hundred minutes, or still further. 



The doses of sulphate of atropia that were given in the four sets of experi- 

 ments of this group that have last been described, namely, 005 gr., 0-5 gr., 1*5 

 gr., and 3 grs., are all included within the range of the doses of this substance 

 able to prevent the fatal effect of one and a half times the minimum-lethal dose of 



65 



, recovery 



90 



, recovery 



95 



, recovery 



100 



„ death 



105 



„ death 



120 



„ death 



