14 BULLETIN 1023, U. S. DEPARTMENT OF AGRICULTURE. 



the presence of food was raised. By using amaranth, which did not 

 form a precipitate with strychnine in the concentration in which it 

 was used, it was possible to trace the course of strychnine down the 

 gastro-intestinal canal. In some instances the dye had penetrated 

 into the duodenum or very close to the pyloris ; in others the antrum 

 of the stomach was filled by well-packed, semidry contents, the dye 

 being in the cardiac and midportions of the stomach. Death in the 

 second case must have been due to absorption directly through the 

 stomach wall. The possibility that the food filtered out the coloring 

 matter as the strychnine solution progressed seems untenable because 

 of the remoteness from the pyloris and the fluid character of the dyed 

 material in contrast with the semidry material in the antrum. Prac- 

 tically it would appear to make little difference whether death ensued 

 by sufficiently accelerating or forcing a gastric absorption by a high 

 concentration or by permitting a small amount to enter the small 

 intestine, or by a combination of both. These results do not indi- 

 cate a marked absorption of strychnine in the stomach, although 

 death may ensue when the dose administered is very much greater 

 than the subcutaneous lethal dose. 



RELATIVE TOXICITY OF STRYCHNINE TO GROUND SQUIRRELS, MICE, AND RATS. 



Table 8 shows the results of experiments on ground squirrels 

 {Citellus richardsoni) , the minimum subcutaneous lethal dose being 

 0.7 milligram per kilo. The data show also that the ground squirrel 

 is four or five times more susceptible to the poison administered 

 subcutaneously than the rat. This is one of the two pharmacological 

 reasons which make the successful poisoning of the rat more difficult. 

 The case of ground squirrels differs somewhat from that of rats, 

 since it has been shown by Piper (17) that the poison is absorbed 

 from the cheek pouches and that the lethal dose is also much less 

 by this route than by the stomach. The range between the highest 

 dose of strychnine survived and the lowest lethal dose in the experi- 

 ments reported by Pierce and Clegg (20) for California ground 

 squirrels {Citellus beecheyi) is so great that no accurate comparison 

 of their data with those here reported can be made. 



According to Falck (6), the toxicity of strychnine administered 

 subcutaneously to the mouse is about four times greater than that 

 here reported for rats. According to Hunt's data (Table 1) it is 

 about two and five-tenths times more toxic. In the experiments 

 herein reported large white and wild mice were tested with the same 

 technique as that used for rats. It was found that 2 milligrams of 

 strychnine sulphate per kilo injected subcutaneously proved fatal, 

 1.5 milligrams being somewhat less certain. For these particular 

 mice strychnine was about half as toxic as it was for rats. 



