566 DR THOMAS R. FRASER ON THE ANTAGONISM BETWEEN 



was 36, and that of the respiratory movements 18. No further observation was 

 made until the seventh day, when it was found that the heart was contracting 

 41 times in ten seconds, that the respirations were occurring 20 times in ten 

 seconds, and that the pupils measured |-§ths x ^Jths of an inch. 



The usual testing experiment to prove that the animal had received a lethal 

 dose of physostigma, was made on the ninth day ; but in this instance a smaller 

 dose was administered than that from which the animal had already recovered. 



Experiment 51-b. — Having ascertained that the rabbit which formed the 

 subject of the preceding experiment now weighed three pounds five ounces 

 and three quarters, I administered to it, by subcutaneous injection, thirteen 

 one-hundredths of a grain of sulphate of physostigmia. In four minutes there- 

 after, the rate of the cardiac contractions had diminished to 34 per ten seconds, 

 and in six minutes to 29 per ten seconds. At the latter time, the limbs of 

 the animal were extended, and it stood or went about unsteadily with the body 

 abnormally elevated. Soon afterwards, it became excited, and went about 

 with hurried stumbling movements; and during these movements, it was found 

 that the heart's action was accelerated to the rate of 44 in ten seconds. In 

 fourteen minutes, pultaceous fasces were passed, moisture appeared at the 

 mouth, frequent fibrillary twitches were occurring, and occasionally moist 

 sounds accompanied the somewhat frequent respiratory movements. In 

 seventeen minutes, the pupils were markedly contracted, and the rabbit lay on 

 the abdomen and thorax. In twenty minutes, tremors frequently occurred, the 

 respirations were now laboured and greatly obstructed by mucus and saliva, and 

 the heart contracted only 16 times in ten seconds. The rabbit was dead in 

 twenty-four minutes. 



Immediately before death occurred, the pupils became dilated to i^yths x 

 ^-g-ths of an inch ; and at the moment of death they became contracted to 

 5 6 i7 x 5 5 oths of an inch. After this, their size diminished to g%ths x 5%ths of an 

 inch, at one minute and thirty seconds ; but soon afterwards, gradual dilatation 

 set in, until they measured g^ths x ^>ths of an inch, twenty-four minutes after 

 death. At this time, post mortem rigor had appeared in the posterior extre- 

 mities (temperature of laboratory, 58° F.) 



In these various experiments, the influence exerted by atropia u}3on the 

 action of physostigma is shown to be a most remarkable and conspicuous 

 one, for it effectually counteracts the lethal activity of certain doses of 

 physostigma, whether it be given within a certain time before, simultaneously 

 with, or within a certain time after that substance. 



Experiments on Dogs. — The experiments I have described, whereby the exist- 

 tence of this counteraction is demonstrated, were performed on rabbits. In 

 the absence of proof to the contrary, and in the absence likewise of any reason- 

 able grounds for entertaining a different opinion, I feel entitled to assume that 

 this counteraction exists in all the species included in the higher subdivisions 



