EXPERIMENTS ON RABBITS. 



17 



Series VII. 



The object of these experiments was the study of the elimination 

 of caffein by the kidney and into the gastrointestinal canal. The 

 contents of the stomach and intestines were carefully removed and 

 separately examined for caffein, while the feces passed after the 

 injection of caffein until the death of the animals were collected and 

 the amount of caffein determined. Only small quantities 1.2 to 

 2 mg were found. The intestinal contents, however, contained 

 appreciable quantities of caffein. The rabbits on the oat diet elim- 

 inated 19.3 mg, or 3.56 per cent, while for those on a diet of carrots 

 only 1.7 per cent of the caffein ingested was recovered, little differ- 

 ence being observed in the percentage, as well as the absolute amounts 

 of caffein recovered from the gastric contents of both groups of rab- 

 bits. Two groups of rabbits were employed, three being fed on oats 

 and three on carrots. Twenty-four hours after having received 150 

 mg of caffein per kilo subcutaneously the animals were killed and the 

 urine, feces, intestinal contents, and stomach contents were examined 

 separately, with the following results: 



SERIES VII. Post-mortem examination of rabbits 24 hours after injecting 150 mg of 



caffein per kilo. 



CAFFEIN RECOVERED. 



Series VIII and IX. 



These rabbits were fed hay exclusively for several days before and 

 after the administration of caffein. In both experiments nearly the 

 entire amount of caffein eliminated was found in the urine of the first 

 twenty-four hours. The diuretic effect of caffein was marked in all 

 of the rabbits except in No. 723 of Series IX, in which the amount of 



