584 



DR THOMAS R. FRASER ON THE ANTAGONISM BETWEEN 



mately be placed among these exceptional results. Several others will after- 

 wards be noted. 



Experiments with Twice the Minimum-Lethal Dose of Physostigma. — When 

 atropia was administered five minutes before a dose of physostigma twice as 

 large as the minimum-lethal, the following results were obtained : — * 



Experiment 102. — With 019 grain of sulphate 



Experiment 103. „ 0-02 „ 



Experiment 104. „ 0-02 „ 



Experiment 105. „ 0-021 „ 



Experiment 106-a. „ 0-025 „ 



Experiment 107. „ 0-03 „ 



Experiment 108-a. „ 0-04 „ 



Experiment 109-a. „ 0-05 „ 



Experiment 110-a. „ 0*3 



Experiment 111-a. „ 1- „ 



Experiment 112-a. „ 2- 



Experiment 113-a. „ 2-3 



Experiment 114-a. „ 3- 



Experiment 115-a. „ 3-2 



Experiment 116. „ 3-3 



Experiment 117. ,, 3-5 



grains 



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One-fiftieth of a grain of sulphate of atropia is therefore too small a 

 quantity to prevent death from following the administration of a dose of 

 physostigma twice as large as the minimum-lethal, but one-fortieth of a grain 

 is sufficient to do so; and doses ranging from one-fortieth of a grain to three 

 grains and a fifth can successfully antagonise this dose of physostigma. 

 When, however, a dose larger than three grains and a fifth is administered, 

 death occurs. Experiment 107 is another instance of an exceptional result 

 being produced. By referring to the description of this experiment in the 

 Tabular Summary, it will be seen that soon after physostigma had been 

 administered, the rabbit became excited and. ran about and struggled ener- 

 getically. Such movements and struggles appear greatly to favour the toxic 

 "action of physostigma ; and it has already been pointed out that when they 

 occur, the minimum-lethal dose of physostigma is appreciably lessened. 



Experiments ivith Two and a half times the Minimum-Lethal Dose of Phy- 

 sostigma. — When two and a half times the minimum-lethal dose of physostigma 

 was administered, the following results were obtained : — t 



Tabular Summary, Series 1, Table 4. 



t Ibid., Table 5. 



