Primary Cleavage Products. 393 
Deuterocaseose was then separated from the filtrate from the acetic 
acid precipitate, by saturation of the fluid with ammonium sulphate, 
as recommended by Neumeister* for deuteroalbumose. It was then 
purified by dialysis, ete., and its reactions carefully studied. So far 
as we could see, it differed from deuterocaseose A and B in two 
respects only, but these points showed so marked a difference it 
was plainly evident that the deuterocaseose separated by ammo- 
nium sulphate was quite different from deuterocaseose A, separated 
by acetic acid. Thus deutero C was not precipitated at all in an 
aqueous solution by acetic acid, nor by acetic acid and potassium 
ferrocyanide, neither was its aqueous solution precipitated by cupric 
sulphate. The significance of these points of difference will be dis- 
cussed later on. After studying the reactions, there was not enough 
substance remaining for analysis. 
Digestion D. 
In this digestion, 2 kilos of freshly prepared casein were used, 
together with 6 litres of 0:4 per cent. hydrochloric acid and an appro- 
priate quantity of strong pepsin solution. The mixture was warmed 
at 45° C. for five hours, then neutralized and filtered from the semi- 
gelatinous residue. 
D. Protocaseose. 
The neutral fluid was concentrated to about 14 litres and then 
filtered from the slight flocculent precipitate which had formed. 
Saturation of the fluid with sodium chloride gave an exceedingly 
heavy precipitate, somewhat more gummy than usual. The entire 
fluid, however, was only partially saturated with salt, with a view 
to see whether the precipitate produced in this manner would agree 
wholly with the precipitate produced on complete saturation. Thus 
a fractional precipitation was made, in which the first fraction 
represents that portion of the caseose precipitated by about two- 
thirds saturation of the fluid with salt. This precipitate was there- 
fore filtered off, washed as usual, dissolved in water and re-precipi- 
tated with salt. As dyscaseose was generally found only in traces, 
the precipitate, after being washed, was dissolved at once in water 
and dialyzed until all chlorine was removed from the solution. On 
opening the dialyzing tubes, quite a large quantity of heterocaseose 
was found adherent to the sides of the paper., The clear solution of 
* See Zeitschrift fiir Biologie, Band xxiii, p. 381. 
TRANS. Conn. AcaD., VoL. VII. 50 Nov., 1886. 
