578 DR THOMAS R. FRASER ON THE ANTAGONISM BETWEEN 



Experiment 52-a. — A dog, weighing 11 lbs., received 015 grain of sulphate of 



atropia, and, five minutes afterwards, 9 grain of sulphate 

 of physostigmia. Recovery took place. 



52-b. — Ten days afterwards, the same dog, now weighing 11 lbs. 

 4 oz., received 0*3 grain of sulphate of physostigmia. 

 Death occurred in seventeen minutes. 

 Experiment 53-a. — A dog, weighing 10 lbs., received 8 grains of sulphate of 



atropia, and, immediately afterwards, 3 grains of extract 

 of physostigma. Recovery took place. 



53-b. — Three weeks afterwards, the same dog, now weighing 

 10 lbs. 2 oz., received 8 grains of sulphate of atropia, 

 and, immediately afterwards, 6 grains of extract of physo- 

 stigma. Recovery took place. 



53-c. — Fifteen days after the second experiment, the same dog, 

 now weighing 10 lbs. 1 oz., received 3 grains of extract of 

 physostigma. Death occurred in seventeen minutes. 

 Experiment 54-a. — A dog, weighing 10 lbs. 3 oz., received 06 grain of sul- 

 phate of physostigmia, and, five minutes afterwards, 3 

 grain of sulphate of atropia. Recovery took place. 



54-b. — Nineteen days afterwards, the same dog, now weighing 

 10 lbs. 4 oz., received 0*3 grain of sulphate of physo- 

 stigmia. Death occurred in twenty minutes. 



Although these experiments clearly demonstrate that atropia is able to 

 counteract the lethal action of physostigma in rabbits and dogs, it is possible to 

 suppose that it will not do so in other animals of equally high development. 

 Some support is given to this surmise by evidence tending to show that the 

 action of atropia in certain animals is different from its action in others. The 

 only difference, however, that is known to exist, is in the lethal activity of the 

 substance, relatively to certain animals; and in rabbits and dogs, this lethal 

 activity is less than in several other animals. Accordingly, if the lethal activity 

 of atropia for rabbits and dogs be increased, and if, notwithstanding this 

 increase, successful antagonism be still produced in them, the only reason for 

 supposing that successful antagonism will not be produced in certain other 

 animals will be shown to be an insufficient one. For any given species of 

 animal, the lethal activity of atropia may be modified by the method of ad- 

 ministration, and it is very much greater when this substance is directly 

 introduced into the blood-stream, than when it is injected under the 

 skin. 



4. The influence exerted on the lethal action of physostigma by atropia 

 injected directly into the blood-stream, was examined by experiments on rabbits. 



