1877.] Ojj [Haynes. 



Writer's Experiments. 



The following experiments were made on rats, cats, rabbits, and dogs. 

 The poisons were invariably injected under the skin. 



The time given refers to the period of the injection of the poison ; or, if 

 more injections than one were made, the time is dated from the first 

 injection. 



In all cases in whicli an animal was killed by strychnia, or nicotin, or 

 by both combined, tlie heart continued to beat for a variable time after 

 respiration had ceased. 



A. 071 Bats. 



The ordinary stable rats were used. First, the minimum fatal dose and 

 the physiological action of nicotin were determined, and, next, the action 

 of nicotin and strychnia combined. 



I. Miniimim Fatal Dose of Stryclinia Suljjhafe on Mats. 



This was found by J. Hughes Bennett {Antagonism of Medicines, Lon- 

 don, 1875, p. 14) to be about 1-60 of a grain of the pure alkaloid. The 

 rats used by Bennett averaged about one ounce more in weight than those 

 employed by the present writer. Of course the dose of the sulphate is 

 proportionally larger. 



II. Minimum Fatal Dose ani Physiological Action of Nicotin on Bats. 



When a small dose of nicotin (TTtl-1000 to TTLl-GOO) is injected into a 

 rat, its respiration becomes labored, and, sometimes, noisy ; and the animal 

 shows signs of prostration, but is able to make voluntary motions. After 

 larger doses (ITtl-600 to TTll-140), conyulsions occur, which may be either 

 clonic or tetanic. The convulsions may be preceded, and are always suc- 

 ceeded, by more or less complete paralysis of motion. One convulsion may 

 terminate life, but, generally, the animal survives througli several convul- 

 sions. The respiration, after each convulsion, ceases for several seconds, 

 and, sometimes, for more than a minute. When death occurs, it is through 

 failure of the respiration. The heart invariably continues to beat for a time 

 after respiration has ceased. Purging and urination are frequent symp- 

 toms. 



From the following experiments, the minimum fatal dose of nicotin, for 

 rats, was found to be about 1-150 of a minim (taking the average weight to 

 be about 10^ ounces). 



