Of more interest physiologically, are the recently discovered nitrogenous bases lysin and lysatinin, or lysatin. These two bodies were first identified by Drechsel[184] and his co-workers as products of the decomposition of various proteids, when the latter are boiled with hydrochloric acid and stannous chloride. They were first obtained by Drechsel as cleavage products of casein.[185] Later, Ernst Fischer,[186] working under Drechsel’s direction, separated them as decomposition-products of gelatin; while Siegfried[187] obtained them as products of the cleavage of conglutin, gluten-fibrin, hemiprotein, and egg-albumin, by boiling with hydrochloric acid and stannous chloride. In all of these cases it is obvious, from the method of treatment pursued, that the two bodies result from a simple hydrolytic cleavage of the proteid molecule. Hence, it might be assumed that these two bases would likewise be formed in trypsin-proteolysis. This assumption, Hedin,[188] working in Drechsel’s laboratory, has proved to be correct, and furthermore he has shown that the amount of these bases formed in pancreatic digestion is not inconsiderable. Thus, as products of the digestion of three kilos. of moist blood-fibrin with an alkaline solution of trypsin, 28 grammes of pure platino-chloride of lysin were obtained, and sufficient lysatinin to establish its identity. [184] Der Abbau der Eiweissstoffe. Du Bois-Reymond’s Archiv. f. Physiol., p. 248. 1891. [185] Zur Kenntniss der Spaltungsproducte des Caseins. _Ibid._, p. 254. 1891. [186] Ueber neue Spaltungsproducte des Leimes. _Ibid._, p. 265. 1891. [187] Zur Kenntniss der Spaltungsproducte der Eiweisskörper. _Ibid._, p. 270. 1891. [188] Zur Kenntniss der Producte der tryptischen Verdauung des Fibrins. _Ibid._, p. 273. 1891.