their passage into the blood or lymph. [210] Ueber die Einführhrung der Albumosen und Peptone in den Organismus, Zeitschr. f. Biol., Band 24, p. 277. [211] Rohmann: Ueber Secretion und Resorption im Dünndarm, Pflüger’s Archiv f. Physiol., Band 41, p. 440. [212] Du Bois-Reymond’s Archiv f. Physiol., p. 33, 1880. Many observations lend favor to the view that a transformation of some kind takes place in the intestine itself, not indeed in the lumen of the tube, but somewhere in the walls, through which the peptones must pass before reaching the blood. Thus, peptones placed in contact with pieces of the isolated, though still living, intestine, after a time completely disappear from view,[213] so completely that no reaction can be obtained even by the most delicate of tests. In support of this statement I may cite the results of several of my own experiments which certainly furnish evidence that true peptones undergo profound alteration by simple contact with the living mucous membrane of the small intestine. The method employed was similar to that made use of some years ago in a study of the influence of peptone on the post-mortem formation of sugar in the liver.[214] A large, well-nourished rabbit was killed by severing the carotid artery and the blood collected and defibrinated. Of this, 50 c. c. were mixed with an equal volume of 0.5 per cent. salt solution containing 1.25 grammes of pure amphopeptone, prepared from egg-albumin, the mixture obviously containing 1.25 per cent. of peptone. The fluid was transferred to a large, roomy flask, provided with a stopper having two holes, in one of which was fitted a long glass tube reaching below the fluid. The flask, with its contents, was then placed in a suitable water-bath at a temperature of 40° C. [213] Salvioli: Eine neue Methode für die Untersuchung der Functionen des Dünndarms, Du Bois-Reymond’s Archiv f. Physiol., 1880. Supplement Band, p. 112. Neumeister: Zur Physiologie der Eiweissresorption und zur Lehre von den Peptonen, Zeitschr. f. Biol., Band 27, p. 324. [214] Chittenden and Lambert: Studies in Physiol. Chem., Yale Univer., vol. i., p. 171.