542 



DR THOMAS E. FRASER ON THE ANTAGONISM BETWEEN 



death, in two other cases recovery followed the administration of 22*5 and of 

 21 grains respectively. It must, therefore, be allowed that the minimum fatal 

 dose has only approximatively been determined. A more accurate determina- 

 tion could not be effected without greatly increasing the number of experiments. 

 Fortunately, however, it was unnecessary to incur the trouble and expense* 

 that would thereby have been entailed, as an approximative determination of 

 the minimum fatal dose of atropia was all that was needed for the purpose of 

 this research.t 



Minimum Lethal Dose of Extract of Physostigma. — The experiments which 

 are mentioned in the next table were undertaken to determine the minimum 

 lethal dose for rabbits of extract of physostigma. 



Number of 

 Experiment. 



Weight of 

 Babbit. 



Actual Dose. 



Dose per 3 lbs. 

 Weight of Animal. 



Result. 



17. 



3 lbs. 3 oz. 



0-8 gr. 



0-7 gr. 



Recovery. 



18. 



3 lbs. 



0-9 gr. 



0-9 gr. 



Recovery. 



19. 



3 lbs. 2 oz. 



0-93 gr. 



0-9 gr. 



Recovery. 



20. 



3 lbs. 8 oz. 



1-2 gr. 



1-02 gr. 



Recovery. 



21. 



3 lbs. 6 oz. 



1-18 gr. 



1-05 gr. 



Recovery. 



22. 



2 lbs. 14 oz. 



1 gr. 



1-05 gr. 



Recovery. 



23. 



3 lbs. 1 oz. 



1-2 gr. 



1-2 gr. 



Deatb, in about 27 minutes. 



24. 



3 lbs. 6 oz. 



1-35 gr. 



1-2 gr. 



Deatb, in about 23 minutes. 



25. 



3 lbs. 5 oz. 



1-32 gr. 



1-2 gr. 



Deatb, in about 33 minutes. 



26. 



3 lbs. 2 oz. 



1-87 gr. 



1-8 gr. 



Deatb, in about 16 minutes. 



The results of these experiments indicate that the minimum lethal dose for 

 rabbits of extract of physostigma is 1 2 grain for every three pounds weight of 

 animal, or 4 grain for every pound. 



Minimum Lethal Dose of Sulphate of Physostigmia. — The minimum lethal 

 dose for rabbits of sulphate of physostigmia was discovered by the experiments 

 that are epitomised in the next table. 



* The price of sulphate of atropia being a little more than fifteen shillings for sixty grains, the ques- 

 tion of expense becomes worthy of consideration. 



"f" The minimum lethal dose of sulphate of atropia, administered subcutaneously, appears to be 

 smaller for dogs than for rabbits. Among other experiments, I have performed the following : — A 

 dog, weighing seven pounds and fifteen ounces, received twenty grains, and recovery followed ; but 

 when a dose of twenty-five grains was given to the same dog, eight days subsequently, death occurred 

 in twenty-three minutes. Another dog, weighing sixteen pounds, which, seven days previously, had 

 recovered after the administration of ten grains, died on the fourth day after it had received fifteen 

 grains. 



