82 R. H. Chittenden — Caseoses, Casein D^speptone, 



This protocaseose is thus seen to have a higher percentage of car- 

 bon than the proto bodies previously* studied, although one prod- 

 uct was then obtained with 53-93 per cent. C, 7' 1 7 per cent. H, and 

 16-05 per cent, N. 



In reactions, likewise, this protocaseose differs somewhat from the 

 protocaseoses previously obtained, and as the characters of the pres- 

 ent body have been verified by the reactions of several other prod- 

 ucts similarly prodiiced, we are led to believe in their constancy. 

 Moistened with water, the powdered protocaseose becomes immedi- 

 ately gummy and soon dissolves to a perfectly clear fluid, which on 

 addition of considerable water becomes decidedly cloudy or tur- 

 bid. Treated with a large amount of water at the outset, the pro- 

 tocaseose dissolves more slowly, giving a more or less turbid fluid. 

 In dilute acid and in dilute sodium carbonate it dissolves to a per- 

 fectly clear fluid. 



Towards heat, aqueous solutions of protocaseose act exactly like 

 protoelastose. Even when warmed very gently, the solution be- 

 comes quickly turbid and if concentrated gives more or less of a floccu- 

 lent precipitate. On cooling, the turbidity disappears, reappearing 

 as the fluid is heated. Like protoelastose also, a solution of the 

 caseose body on being rapidly concentrated deposits more or 

 less of the substance as a gummy mass, which, however, will dis- 

 solve in cold water, or if the fluid is not too concentrated will dis- 

 solve in the mother liquid as it cools. Dilute acetic acid added to 

 an aqueous solution of protocaseose gives no precipitate whatever, 

 but potassium ferrocyanide added to the acid fluid gives a heavy 

 precipitate. 



Dilute hydrochloric acid produces no precipitate. 



Dilute nitric acid added to an aqueous solution of the caseose 

 gives a heavy white precipitate, which on gently warming, quickly 

 dissolves while the fluid takes on a faint pink or rose color, wliich 

 on further warming changes to a bright yellow or reddish yellow 

 color. If the nitric acid solution is not warmed too long, the pre- 

 cipitate reappears as the mixture cools. 



Solution of cupric sulphate gives a heavy, greenish white precipi- 

 tate when added to an aqueous solution of protocaseose. 



As already stated, the first precipitates of protocaseose obtained 

 by saturating the neutralized digestive fluid with salt, were not en- 

 tirely soluble in water; a small residue remained, apparently 



* See Chittenden and Painter. Studies from Laboratory of Physiological Chem- 

 istry, Yale University, vol. ii, p. 197. 



