400 Chittenden and Painter— Casein and its 
solved in water and dialyzed until the greater portion of the salt was 
removed. The solution was then concentrated and the substance 
reprecipitated by saturating the neutrai solution with ammonium 
sulphate. This precipitate, after solution in water, was then dialyzed 
until all of the ammonium sulphate was removed, after which the 
solution was concentrated and precipitated with alcohol. When 
dry, the substance gave by analysis the results shown in the accom- 
panying table. 
This body differs from all of the preceding preparations, in that it 
is not precipitated from an aqueous solution by acetic acid. Neither 
is it precipitated at all by the addition of salt in substance; but the 
addition of a little acetic acid to the salt-saturated fluid gives a heavy 
precipitate which, however, does not represent all of the deutero- 
caseose, since the filtrate gives an additional precipitate with 
ammonium sulphate. Apparently about one-half of the substance is 
precipitated by acetic acid. Further, the acetic acid precipitate 
in this case differs from the protocaseose precipitate with acid, in that 
it is readily and completely soluble in water. This body, therefore, 
which certainly must represent pure deuterocaseose, shows a close 
resemblance to the pure deuteroalbumose separated by Neumeister. 
Like the latter, it does not give any precipitate whatever with cupric 
sulphate nor with ferric chloride and only the faintest turbidity with 
acetic acid and potassium ferrocyanide. 
D. Heterocaseose. 
In each digestion, evidence was obtained at various points in the 
process of separation, noticeably on dialysis of the first protoalbumose 
precipitate, of the presence of a body insoluble in water but soluble 
in dilute sodium chloride solution. The quantity of the sub- 
stance, however, was in most cases exceedingly small, so much so 
that nothing more than a few reactions could be tried with it. In 
the present digestion, however, the amount was somewhat larger, 
and sufficed for a partial analysis. The substance was obtained as a 
more or less gummy residue, on dialysis of protoalbumose 1. 
It was purified by solution in 10 per cent. sodium chloride and 
separation by dialysis. Like heteroalbumose, the whole of the 
substance was not now soluble in salt solution, for a portion had 
apparently been converted into a body resembling dysalbumose, 
insoluble in salt solution but soluble in 0°2 per cent. hydrochloric 
acid. 
