256 THE INCOME OF ENERGY 



with the biuret reaction. No peptone will be 

 found. 1 



An examination of the lymph would show 

 that it also contains no peptone. Apparently 

 the peptone absorbed from the intestinal loop is 

 changed in its passage through the intestinal 

 wall. This conclusion is made secure by the ex- 

 periments of Salvioli, 2 who removed the jejunum 

 of the dog or rabbit, tied a cannula in the mesen- 

 teric artery and vein, and established through 

 these vessels an artificial circulation of defibri- 

 nated blood diluted with isotonic saline solution. 

 One gram of peptone was dissolved in 10 c.c. of 

 normal saline solution and placed in the intes- 

 tine, and the artificial circulation maintained four 

 hours. The peptone disappeared from the intes- 

 tine, but none could be found in the blood. 



Albumose and Peptone changed in their Passage 

 through the Intestinal Wall. Kill a fairly large 

 anaesthetized rabbit by bleeding. Beat the blood 



solution is free from lead, but usually still contains a trace of 

 yellow pigment. Apply the biuret reaction as above. If the 

 urine requires to be concentrated, it is better to evaporate the 

 final ammonium sulphate filtrate, as boiling the urine at first 

 deepens the color. (Neumeister and Shore, loc. cit.) 



1 NEUMEISTER : Zeitschrift fur Biologie, 1888, xxiv, pp. 

 278-279. 



2 SALVIOLI : Archiv fur Physiologic, 1880, Supplemental 

 volume, p. 112. 



