600 



T>R THOMAS R FRASER ON THE ANTAGONISM BETWEEN 



simultaneously. — In the experiments of this group/ 1 '" the administration of the 

 two substances was effected in exactly the same manner as in experiments 

 44-# and 45-#, Section A (pp. 553 and 555). Before mentioning the results 

 that were obtained, it is proper to point out that a brief interval necessarily 

 elapsed between the administration of the two substances. This interval, 

 however, was only one of a few seconds, and, practically, was of little moment, 

 especially as uniformity was obtained in all the experiments by care being taken 

 always to inject the dose of atropia before that of physostigma. When, with 

 this precaution, a dose of physostigma one and a half times as large as the 

 minimum-lethal (012 grain of sulphate of physostigmia per three pounds weight 

 of rabbit), was administrated nearly at the same moment with various doses of 

 sulphate of atropia, the following results were obtained : — 



Experiment 247. — With 0-02 grain of sulphate of atropia, death occurred. 



Experiment 248. „ 0-02 



Experiment 249-a. „ 0*05 



Experiment 250-a. „ 5 



Experiment 251- a. „ 1- 



Experiment 252-a. ,, 1-5 



Experiment 253-a. ,, 2- grains 



Experiment 254-a. „ 2*5 



Experiment 255-a. „ 3* 



Experiment 256-a. „ 33 



Experiment 257. „ 3-5 



Experiment 258. „ 4- 



Experiment 259. „ 4-5 



Experiment 260. „ 5- 



death 



recovery 



recovery 



recovery 



recovery 



recovery 



recovery 



recovery 



recovery 



death 



death 



death 



death 



It is shown by these experiments that when a dose of physostigma one and 

 a half times as large as the minimum-lethal is administered simultaneously with 

 sulphate of atropia, one fiftieth of a grain of the latter substance is a dose 

 insufficient to prevent death, but that one twentieth of a grain is a dose 

 sufficiently large to do so. It is likewise shown that the fatal effect of 

 this dose of physostigma may be prevented when any dose of sulphate of 

 atropia ranging from one twentieth of a grain to three grains and three tenths 

 is given simultaneously with it, and that death occurs when the dose of sulphate 

 of atropia is three grains and a half or greater than this. 



(b) Experiments in which Atropia was administered after Physostigma. — A 

 considerable amount of interest is attached to the experiments of the next 

 group, in which the administration of physostigma preceded that of atropia. t 

 In briefly describing these experiments, I shall, in the first place, consider the 



* Tabular Summary, Series iii. Table 1. 



t Ibid. Table 2. 



