540 



DR THOMAS R. FRASER ON THE ANTAGONISM BETWEEN 



tain limits, of the substance absorbed into the blood, but also the process of 

 absorption is commenced directly after the injection is effected. Further, it 

 has the great advantage of convenience, wherein it is greatly superior to the 

 method by introduction into the stomach. 



Chief Objects of the Research. — As evidence was obtained at an early period 

 in this research of the existence of an antagonism between the general actions 

 of physostigma and atropia, a wide field for further investigation was thereby 

 opened up. In the experiments that will be described in the first portion of 

 this communication, I shall endeavour to show, as clearly as possible, that 

 atropia possesses, in a remarkable degree, the power of counteracting the lethal 

 action of physostigma. In the subsequent portion of the communication the 

 extent of this power will be examined and its limits defined. 



Section A.— EXAMINATION OF THE INFLUENCE OF ATROPIA UPON THE 

 LETHAL ACTIVITY OF PHYSOSTIGMA. 



Determination of the Minimum Lethal Doses of the Preparations. 



In accordance with the plan that has been adopted for this research, several 

 preliminary experiments were made in order to determine the minimum lethal 

 dose for rabbits of each of the preparations employed. For the present pur- 

 pose it is sufficient to mention only the leading results of these experiments. 



Minimum Lethal Dose of Sulphate of Atropia. — In the following table a 

 summary is given of experiments undertaken to determine the minimum lethal 

 dose for rabbits of sulphate of atropia. 



Number 

 of Experi- 

 ment. 



Weight of 1 

 Rabbit. . 



Actual Dose. 



Dose per 



3 lbs. Weight 



of Animal. 



Result. 



Notes. 



1. 



4 lbs. 13 oz. 



4 grs. 



2 - 49 grs. 



Recovery. 



The only effects were dila- 

 tation of tbe pupils, slight 

 restlessness, and accelera- 

 tion of the cardiac contrac- 

 tions and of the respira- 1 

 tions. 



2 



4 lbs. 10 oz. 



5 grs. 



3-24 grs. 



Recovery. 



Do. 



3. 



4 lbs. 8 oz. 



9 grs. 



6 grs. 



Recovery. 



Do. Also some obvious 

 symptoms of visual de- 

 rangement. 



4. 



3 lbs. 



6*5 grs. 



6 '5 grs. 



Recovery. 



Distinct, though unim- 

 portant, paralytic symp- 

 toms were produced, the 

 respirations were reduced 

 in frequency, the cardiac 

 action was accelerated, 

 and the pupils were 

 dilated. 



5. 



3 lbs. 5 oz. 



7*9 grs. 



7"5 grs. 



Recovery. 



Do. 



