Investigations on Gelatin

RECENT investigations carried out in this laboratory indicate that gelatin consists of molecules, or aggregates of molecules, which readily undergo intramolecular change. It has been shown, for example, by Knaggs [1923] that if gelatin is hydrolysed rapidly by throwing it into boiling 25 % hydro- chloric acid solution, it yields a distinctly smaller fraction of basic products precipitable by phosphotungstic acid than it yields when it has been allowed to stand with the cold acid solution before boiling. This phenomenon has been further investigated by Schryver and Thornley [1927] has found that the treatment of gelatin with relatively dilute cold solutions of acids or alkalis can give rise to changes in the amounts of basic products obtained when the sample thus treated is afterwards submitted to rapid hydrolysis with strong acids. Furthermore, Knaggs and Schryver [1924, 1] have shown that when gelatin is heated in water and then hydrolysed by boiling acids in the usual way, there is in the hydrolysis products more nitrogen in the form of non-amino-nitrogen than in those obtained in a similar way from gelatin not previously heated with water-indicating that this comparatively mild treatment causes the forma- tion of stable nitrogenous rings, which are not opened up by subsequent hydrolysis with strong acids. ELECTROLYSIS OF GELATIN HYDROCHLORIDE AND SODIUM GELATINATE.