ELIMINATION OF CAFFEIN IN NEPHRECTOMIZED RABBITS. 9 



be regarded as of any value in furnishing evidence of the existence 

 of a compensatory mechanism in the stomach and intestines. Evi- 

 dence that the gastrointestinal canal is a channel of elimination in 

 pathological conditions was furnished recently by Grigaut and Richet 8 

 in a series of experiments on dogs which had been starved for 24 

 hours and operated upon under anaesthesia. After the subcutaneous 

 injection of sodium chlorid, urea, and glucose, these substances were 

 found in the intestines, and the first two also in the stomach. The 

 very recent work of Roger and Gamier 25 lends support to the con- 

 tention that a compensatory mechanism of elimination is present in 

 the intestines when the kidneys are removed. In experiments car- 

 ried out on rabbits having both kidneys removed, 200 cc of fluid 

 were found in the upper part of the small intestine after the infusion 

 of large quantities of Locke's solution. With similar treatment of 

 rabbits with kidneys intact the amount of fluid did not exceed 40 cc. 



From what has already been stated, it is clear that vicarious action 

 or compensatory elimination by the stomach and intestines undoubt- 

 edly takes place when the kidney is abnormal or absent. Evidence 

 is accumulating, however, to prove that this is not universally the 

 case; in all probability such a mechanism does exist for some sub- 

 stances but apparently fails to develop for others. It is interesting 

 to recall here the views of Bouchard 7 on this subject, as he long 

 ago denied the existence of vicarious elimination by the gastrointes- 

 tinal canal or by the skin in conditions of renal insufficiency, for he 

 believed that an increased quantity of fluid which may be secreted 

 by these organs under such conditions does not necessarily mean 

 augmentation of the amounts of the solid substances dissolved. He 

 therefore maintained that these organs do not supplement the func- 

 tions of the kidney. The experiments of Meltzer and Lucas 17 with 

 magnesium sulphate showed that this substance is much more toxic 

 for nephrectomized rabbits, the toxicity under these conditions being 

 increased 50 per cent. The absence of vicarious elimination is also 

 indicated in experiments with subminimum doses of this salt. Ani- 

 mals that received small doses at intervals of several hours suc- 

 cumbed when the sum was equal to the maximum toxic or fatal dose. 

 Studies on the elimination of radium by Salant and Meyer 26 have 

 likewise shown that new paths for the elimination of this substance 

 are not developed in the rabbit after the removal of both kidneys. 



In a recent communication on the elimination of nitrogen and 

 sodium chlorid by the skin in cases of chronic nephritis, Loofs 14 

 stated that the quantities present in this condition were the same as 

 in healthy subjects. There is, perhaps, a difference in the mechanism 

 for the elimination of various substances, organic and inorganic, in 

 disease. The following investigation shows, however, that such dif- 

 ferences exist also in health, as has long been established for a number 

 70395 Bull. 16& 13 2 



