THE ACTIONS OF PHYSOSTIGMA AND ATROPIA. 607 



sulphate of physostigmia both when the atropia is administered five minutes 

 before the physostigma, and when the two substances are simultaneously 

 administered. The dose with which the last-mentioned experiments were 

 performed, namely, three grains, is, however, near the maximum limit of the 

 range in the case of simultaneous administration, and, accordingly, not far from 

 this limit in the case where atropia is administered five minutes before physo- 

 stigma. 



I have in the next place to describe two sets of experiments made respec- 

 tively with one and the other of two doses of sulphate of atropia greater 

 not only than the maximum dose that produces successful antagonism when 

 given simultaneously with one and a half times the minimum-lethal dose of 

 physostigma, but also than the maximum that does so when given five minutes 

 before it. 



The first of these doses of sulphate of atropia is four grains and a half. It 

 was administered before physostigma at the intervals and with the results that 

 will now be stated : — 



Experiment 314 — With an interval of 10 minutes, death occurred. 

 Experiment 315-a. „ 15 „ recovery „ 



Experiment 316-a. „ 15 „ recovery „ 



Experiment 317- a. „ 20 „ recovery „ 



The very interesting and remarkable character of the results of these experi- 

 ments becomes apparent when they are considered along with those of two 

 experiments previously described, in which the same closes of sulphate of 

 atropia and sulphate of physostigmia respectively were administered. In the 

 first of these (Experiment 259), the administration of the two substances was 

 simultaneously effected, and in the second (Experiment 288), the atropia was 

 administered five minutes before the physostigma ; and in both cases death 

 occurred. It has now been shown that when, with the same respective doses, 

 the atropia is given ten minutes before the physostigma, the result is still a 

 fatal one ; but that when the atropia is given fifteen or twenty minutes before 

 the physostigma, recovery, and not death, occurs. 



I have not made any experiments with this dose of sulphate of atropia for 

 the purpose of determining the maximum interval of time that may, without 

 hindering the production of successful antagonism, be allowed to intervene 

 between its administration and the subsequent administration of one and a half 

 times the minimum-lethal dose of sulphate of physostigmia. 



Such a determination, however, was accomplished in the experiments where 

 the dose of sulphate of atropia was five grains. The intervals of time separating 

 the administration of the two substances, and the results obtained in these 

 experiments, were as follows : — 



