26 



THE TOXICITY OF CAFFEIN. 



TABLE 1. Subcutaneous injections of caffein rabbits Continued. 



SERIES D. 



SERIES E. 



ADMINISTRATION BY MOUTH. 



These experiments were carried out on two varieties of rabbits, the white and the 

 gray. The diet consisted chiefly of oats, but in a few cases carrots formed the exclusive 

 diet. Food and water were given ad libitum. A 2 per cent solution of caffein was 

 administered through a stomach tube. Since the resistance to most drugs is com- 

 monly supposed to be greater when given by mouth than when administered by any 

 other path, doses of 175 to 200 mg per kilo were fed in a series of preliminary experi- 

 ments, all of which were performed on gray rabbits weighing from 865 to 1,135 grams, 

 and which were fed carrots for several days previous to the experiment. Three of the 

 rabbits survived, two without showing any symptoms; in the other case paralysis of 

 the posterior extremities was observed five hours after he received caffein and he was 

 found dead the next morning. Unfortunately no autopsy was performed. The low 

 resistance to caffein of this animal was probably due to some abnormal condition which 

 developed about the time of the experiment, since this rabbit received 325 mg of 

 caffein per kilo two weeks previously and increased reflexes only were observed as a 

 result of this treatment. Hence 200 mg of caffein per kilo can not be considered the 

 toxic dose when fed by mouth. In the following experiments larger doses were 

 therefore given. 



SERIES A. 



Rabbit 248. Belgian hare. Weight, 1,170 grams. Diet, oats. 



November 17: 1.20 p. m., 19.5 cc 2 per cent caffein (330 mg per kilo) administered 

 by the mouth; 4.30 p. m., somewhat hypersensitive. 



November 19: No symptoms; at 9 a. m., urine collected, no reduction of Fehling's 

 solution; rabbit survived. 

 Rabbit 241. White male. Weight, 1,380 grams. Diet, oats. 



November 17: 1.15 p. m., 20 cc 2 per cent caffein (290 mg per kilo) administered 

 by the mouth; 4.30 p. m., some hypersensitiveness, but no other symptoms. 



November 18: 9 a. m., urine collected, no reduction of Fehling's solution; no 

 symptoms; rabbit survived. 



