12 



THE ELIMINATION OF CAFFEIN/. 



Series I. — Three rabbits (Nos. 607, 608, and 619), each receiving 150 mg ofcaffein per 



kilo subcutaneously. 



Diet and time. 



Caffein recovered. 



Remarks. 



Mg 



Percent. 



Oats: 



28.8 

 15.0 



3.80 



5.80 



[Composite urines in three hours, 250 cc. Nos. 607 and 608 had 

 1 convulsions and died during the night. No. 619, which re- 

 1 ceived 240 mg caffein, was run alone for the 22-hour period. 

 [ Total of 760 mg of caffein injected. 



22 hours 



Total 



9.60 







39.3 

 57.13 





Carrots: 



4.75 



• 6.88 



11.63 



\ Composite urines in three hours, 360 cc. Total of 830 mg of 

 j caffein injected. 



22 hours 



Total 









Series II. 



The object of this series was to ascertain when the elimination of 

 caffein began and the length of time during which it continued. The 

 urines at the end of the first hour as well as at the end of 49 hours 

 were examined for caffein. In the oat-fed rabbits 36 mg, or 4.8 per cent, 

 were ehminated during the first hour. In the parallel experiment, in 

 which carrots were fed, only 2 per cent of the caffein administered 

 was found in the urine at the end of the first hour. The urine of the 

 next 24 hours contained 7.18 and 9.23 per cent in the case of the 

 rabbits on oats and on carrots, respectively. At the end of 49 hours 

 the amounts of caffein recovered were 1.94 per cent in the experiment 

 with oats and 1.29 per cent in that on carrots. 



The total amounts of caffein recovered in the entire period showed 

 that the rabbits which were fed oats eliminated about 1.5 per cent 

 more than those fed on carrots. The loss of some of the urine in the 

 latter case makes it probable that the difference was smaller than 1.5 

 per cent. The results of this series indicate, therefore, that the 

 amounts of caffein which are eliminated unchanged may be inde- 

 pendent of the diets employed in these experiments. 



Series II. — Three rabbits (No. 619 of Series I being used again); earn received 150 mg 



per Jcilo subcutaneously. 



Diet and time. 



Caffein recovered. 



Remarks. 



Mg 



Percent. 



Oats: 



36.00 



55.18 

 14.33 



4.87 

 7.18 

 1.94 





25 hours 



49 hours 



1 Composite urine in 1 hour amounted to 111 cc. Total caffein 

 j injected 740 mg. 



Total 



13.99 







14.7 



67.4 



6.3 





Carrots: 



2.00 

 9.23 

 1.29 



("Total caffein injected, 730 mg. No. 629 found dead on second 



25 hours 



49 hours 



1 day; the 49-hour interval was continued on the other two 

 | (490 mg injected); in 25-hour interval there was loss due to 

 I overflow. Composite urines in 1 hour, 100 cc. 



Total 



12.52 











