ELIMINATION OF CAFFEIN IN NEPHRECTOMIZED RABBITS. 15 



after injection, and that caffein is reabsorbed later from some part 

 of the gastrointestinal canal. 



ELIMINATION OF CAFFEIN IN 6 HOURS (SERIES VII). 



Three rabbits were nephrectomized by lumbar incision, the oper- 

 ation requiring on an average 20 minutes. The animals were then 

 injected with caffein subcutaneously, receiving 200 mg per kilo, and 

 were chloroformed at the end of six hours. Rabbit No. 778 became 

 strongly hypersensitive shortly after injection and remained in that 

 condition to the end. Rabbit No. 779 behaved similarly, though the 

 degree of hypersensitiveness was less. Rabbit No. 780 showed the 

 same symptoms and in addition had a short convulsion. 



SERIES VII. Ca/ein recoveredin nephrectomized rabbits which had received 200 mg per kilo. 



Although the difference in the rate of elimination as compared 

 with that in Series IV and V is not very great, it is of sufficient impor- 

 tance to merit attention. Representing the average of three experi- 

 ments, it is not to be regarded as accidental. Moreover, it may be 

 noticed that the amounts racovered were especially diminished in the 

 intestines. It is quite possible, therefore, that the progressive dimi- 

 nution in the amounts of caffein present in the stomach and intestines 

 was due to reabsorption. To test the validity of this hypothesis experi- 

 ments were performed in which the elimination of caffein was studied 

 after longer intervals of time. This was accomplished by collecting 

 and examining the feces in each case until the rabbit died. The 

 stomach contents as well as the contents of the intestines were then 

 examined separately for caffein. The results are shown in detail in 

 the next series of experiments. 



ELIMINATION OF CAFFEIN IN 21 HOURS, 5 AND 7 DAYS (SERIES VIII). 



To explain the absence of caffein in the stomach and intestines in 

 rabbits Nos. 775 and 777 and the recovery of small quantities only 

 in the feces collected since its administration until the death of the 

 animals, it must be assumed that it is either reabsorbed into the cir- 

 culation or decomposed in the lumen of the gastrointestinal canal. 

 As the latter hypothesis is highly improbable, since caffein is known 



