10 BULLETIN 1023, IT. S. DEPARTMENT OF AGRICULTURE. 



elsewhere reported, in which the cages were not inverted, were much 

 less concordant. As a further test, several rats were shaken from 

 the sides of the cages to which they were tightly holding, with the 

 production of fatal spasms. These observations on the rat seem to 

 be in harmony with the fact that but few investigators have 

 .mentioned the conditions under which their animals were kept 

 during the experimental period. Different conditions of experimen- 

 tation may account for a variation in the size of the minimum lethal 

 dose and the occurrence of convulsions from a sub-lethal dose. Xo 

 tests were made, however, on other species for the purpose of repro- 

 ducing some of the inconcordant data in the literature. Although 

 rabbits, guinea pigs, and dogs are unable to grasp as well as climbing 

 animals (cats and rats), it would seem advisable in all cases to select 

 an environment offering the opportunity obtaining in nature. 



Since it is possible to produce or hasten death by producing spasms, 

 a few experiments were conducted to see if life could be prolonged 

 by enforcing quiet. Several rats were given 4 milligrams of strych- 

 nine sulphate per kilo and placed on a slippery glass plate. In due 

 time a sudden jump in the air and violent tonic convulsions resulting 

 in death occurred. Previously the rats had stood practically motion- 

 less except for the movements of respiration. These results show 

 the impracticability of securing survivals from more than a lethal 

 dose by maintaining a volitional but forced quiet, because uncon- 

 trollable and involuntary motions will occur and start the vicious 

 cycle of convulsions. Nevertheless, adult rats may be more or less 

 influenced by the environment of and procedures resorted to in the 

 experiment, and low results may be obtained. 



In the experiments which were performed at various times in the 

 year and on rats on different diets, no variation in the size of the 

 lethal dose which could be assigned to dietary seasonal influences 

 was obtained. 



TOXICITY OF STRYCHNINE ADMINISTERED ORALLY. 



Tables 5 and 6 show the results of administering strychnine sul- 

 phate and strychnine alkaloid orally. 8 The attempt to obtain rats 

 with food in the stomach was not always successful, particularly in 

 the case of wild rats. While some fatalities presumably were caused 

 indirectly by the absence of food from the stomach, as well as by 

 accidentally forcing the injected material beyond the pyloris, this 

 error is automatically ruled out when the percentage of deaths is 

 near the maximum. The. data in the two tables agree in general, in 



8 For various reasons it was not feasible to depend upon feeding experiments. The 

 reliability of the stomach tube as a means to obtain accurate data was shown in a 

 previous report (23). 



