CLE A VAGE THE OR Y OF PRO TEID DIGESTION. 4 1 3 
solution is precipitated by saturation with sodium chloride, so throwing out 
all the heteroalbumose and part of the protoalbumose which are separated 
by dialysis. In the filtrate from saturation with sodium chloride in neutral 
solution are the remainder of the protoalbumose and the whole of the deutero- 
albumose; to this, acetic acid solution, which has been saturated with sodium 
chloride, is added, till a small portion filtered through a dry filter paper no 
longer gives a precipitate with copper sulphate solution. 1 The mixed pre- 
cipitate olproto- and rfettferoalbumoses is now filtered off, and deuteroalbumose 
is isolated from the filtrate by neutralising, dialysing off the sodium chloride, 
and precipitating by saturating with ammonium sulphate, or by adding excess 
of alcohol. 
This method of separating the albumoses may be shown schematically 
thus : — 
Mixed Albumoses 
(saturated with sodium chloride in neutral solution) give 
Heteroalbumose and Protoalbumose Protoalbumose and Deuteroalbumose 
(Precipitate). (Filtrate). 
On dialysis, the solution of these two On adding acetic acid in saturated sodium 
gives chloride, this solution gives 
II II 
Heteroalbumose Protoalbumose Protoalbumose and Deuteroalbumose 
(Precipitate). (Solution). Deuteroalbumose (dialysed and pre- 
(not further treated) cipitated by alcohol) 
(Precipitate). (Filtrate). 
Neunieister also tested the action of hydrolysing agents on pure proto- and 
7teferoalbuinoses prepared as has just been described. He showed that boiling 
for three-quarters of an hour with 5 per cent, sulphuric acid was sufficient 
to convert protoalbumose into deuteroalbumose accompanied by some peptone. 
This was shown by the absence of turbidity on dialysis after neutralising 
(absence of heteroalbumose), by saturation in neutral solution with sodium 
chloride causing no precipitate (absence of protoalbumose), and by precipitation 
occurring on making the saturated solution in sodium chloride acid with acetic 
acid (presence of deuteroalbumose). In a similar fashion the conversion of 
heteroalbumose into deuteroalbumose, by boiling with acid, was demonstrated ; 
here a considerable formation of antialbumid was observed during the process. 
On peptic digestion proto- and het eroalhumose each yielded a deuteroalbumose, 
but they behaved differently towards trypsin. In the case of heteroalbumose, 
a specific point coitld easily be determined, in the course of digestion with 
trypsin in 0*2 per cent, sodium carbonate solution, when, in the presence of a 
considerable quantity of peptone, only deuteroalbumose was present; on the 
other hand, deuteroalbumose could not be obtained in large quantity by the 
action of trypsin on protoalbumose ; the products obtained were chiefly amido- 
acids accompanied by a little peptone, this being probably due to the ease 
with which the deuteroalbumose formed from protoalbumose undergoes decom- 
position. 
Neumeister confirms the results obtained by Kiihne and Chittenden, that 
heteroalbumose is principally an antialbumose, but has some hemialbumose 
mixed with it, while the composition of protoalbumose is the exact reverse, 
it being essentially a hemialbumose, always accompanied, however, by some 
antialbumose. The yield of unalterable peptone was, however, so small in 
some experiments as to induce Xeumeister to believe that perfectly pure proto- 
albumose would contain only hemi groups, or, in other words, be completely 
convertible by tryptic digestion into amido-acicls. The deuteroalbumose 
1 This is a much more delicate test for protoalbumose (given by 1 in 5000) than acetic 
acid and saturated sodium chloride solution (1 in 2000). 
