TOXICITY OF STRYCHNINE TO THE RAT. 



15 



The lethal dose per os was approximately three to five times the 

 subcutaneous dose. Both the subcutaneous and oral experiments 

 bore out the inference to be drawn from Boelter's statement (3) 

 that when administered orally it usually acts more quickly in mice 

 than in rats. Owing to the great number of experiments required 

 and the inability to obtain very large specimens, no attempt was 

 made to study the effect of size, strain, and experimental technique 

 upon the toxicity of strychnine to mice. Undoubtedly, however, 

 the mice which have thus far been tried are more susceptible than 

 rats and apparently they should be three or four times as easy to 

 poison as rats. 



Table 8. — Toxicity of strychnine sulphate administered subcutaneously to male 

 Richardson ground squirrels (Citellus richardsoni) . 1 



Date. 



Weight 



of 

 squirrel. 



Strychnine sulphate solution 

 injected. 



Result. 



1920. 

 Aug. 6 



Sept. 8.. 



Do 



Aug. 6 



Do 



Do 



Grams. 

 160 



280 

 339 



Per cent. 

 0.05 



.02 

 .02 



184 

 240 

 190 



Cc. 

 0.32 



1.25 

 1.18 



1.29 

 1.44 

 .95 



Milligram 

 per kilo. 

 1.0 



.9 



.7 



Fatal spasm began in 28 minutes; 

 dead in 30 minutes. 



Fatal spasm began in 11 minutes; 

 dead in 12 minutes. 



Several mild spasms; partial abil- 

 ity to recover; dead in 18 min- 

 utes. 



Hyperexcitability only; lived. 



Lived. 

 Do. 



Acknowledgment is due Vernon Bailey, of the Bureau of Biological Survey, for procuring these animals. 



STRYCHNINE BAITS. 



White rats were given 1 per cent strychnine bait in the form of 

 soft, mealy food containing about 20 per cent of fat. These rats 

 were accustomed to such a diet, without the strychnine. That the 

 bait was distasteful to them was evident from the way they rubbed 

 their mouths on the floor and sides of the cage. Within about 15 

 minutes most of the rats were unusually excitable and some had 

 sought the wire netting on the sides of the cages for support, indi- 

 cating that part of the strychnine bait had been consumed and 

 strychnine absorbed. 



Obviously this muscle tenseness and excitability might cause the 

 animal to become suspicious and cease eating. Strychnine baits of 

 a type favoring rapid consumption are preferable. Although the 

 food was left in the cages for more than 18 hours, only a few rats 

 died. These results agree with those of practical tests showing that 

 strychnine bait is not well eaten by rats. So much of the food was 

 scattered that no attempt was made to estimate that which remained 

 uneaten. 



