16 



THE ELIMINATION OF CAFFEIN. 



Series VI. 



The rabbits in these experiments were fed caffein by mouth. The 

 feces as well as the urine were examined for caffein. It will be noticed 

 that the weights of the rabbits employed in these experiments differed 

 but little, all of them being of medium size and of the same age. The 

 amounts of cafTein eliminated by the two groups of rabbits differed 

 considerably, as at the end of twenty-four hours a little over 13 per cent 

 of cafTein was found in the urine of the rabbits fed on carrots, while 

 those on oats eliminated in the urine during the same time only 8.02 

 per cent. The amounts of cafTein recovered from the urine during the 

 next twenty-four hours were 1 per cent for those fed on carrots and 0.9 

 per cent for those which were given oats. Although the latter con- 

 tinued to eliminate cafTein in the urine during the following 24-hour 

 period the amount was rather small. Xone was found hi the urine 

 of the other rabbit during this period. It may be concluded, there- 

 fore, that the elimination of cafTein is practically completed within 

 forty-eight hours and does not continue beyond this time. Exami- 

 nation of the feces indicates the presence of appreciable amounts 

 of cafTein, which is probably due to excretion into the gastrointes- 

 tinal canal as well as to lack of absorption. It will be noticed that 

 the rabbits which received oats eliminated apparently more cafTein in 

 the feces than those whose diet consisted of carrots, which is in all 

 probability due to the difference in the ehmination of cafTein by the 

 gastric and intestinal epithelium on an oat than on a carrot diet. 



Series VI. — Babbits to which 150 mg of caffein per kilo were administered by mouth. 



Rabbit No. and diet. 



Time. 



Amount 

 eaten. 



Urine. 



Feces. 



Caffein recovered in 

 composite sample. 



In urine. In feces. 



Carrots: 

 710.. 



711. 



712 



Total. 



Grams. 

 1.485 

 1.3S5 

 1.440 

 1.520 

 1.660 

 1.580 

 1.640 

 1.700 

 1.400 

 1.390 

 1.405 

 1.465 



Hrs. 



Grams. 



1 





24 



130 



48 



300 



72 



450 



1 

 24 





200 



48 



300 



72 



400 



1 





24 



250 



48 



300 



72 



350 



40 



Grams. 



180 





150 



300 



10 



40 





910 





175 

 995 



10 



40 





240 

 200 

 300 



10 

 10 



2.100 



1.025 

 12.000 i 

 1.000 

 0.000 



14. 025 



14 825 



0.60 

 .20 

 .00 



Oats: 



713 



714 



f 1.265 

 \ 1.240 



1.225 

 f 1.285 

 \ 1.240 



1.370 

 f 1.370 

 \ 1.205 

 1 1. 150 



24 

 48 

 72 

 24 

 48 

 72 

 24 

 48 

 72 



Fair. 



Fair. 

 Good. 

 None. 

 Some. 

 Some. 

 None. 

 None. 

 None. 



(?)175 

 tb 

 75 

 90 

 50 



Lost. 

 115 

 25 

 25 



20 ] 

 25 

 25 

 50 



8.02 

 .90 

 .56 





.934 

 .300 



715 



10 

 10 



.200 



















Total 









630 



140 



9.48 1 



1.434 











10. 



914 





