CLEA VAGE THEOR Y OF PROTEID DIGESTION. 413 



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 nitrate from saturation with sodium chlori'de 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 of proto- and eZe^eroalbumoses 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 



Heteroalbumose Protoalbumose Protoalbumose and Deuteroalbumose 



(Precipitate). (Solution). Deuteroalbumose (dialysed and pre- 



(not further treated) cipitated by alcohol) 

 (Precipitate). (Filtrate). 



Neumeister also tested the action of hydrolysing agents on pure proto- and 

 /ieferoalbumoses 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 T^eroalbumose each yielded a deuteroalbumose, 

 but they behaved differently towards trypsin. In the case of heteroalbumose, 

 a specific point could 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 Neumeister to believe that perfectly pure proto- 

 albumose would contain only hemi groups, or, in other words, be completely 

 convertible by tryptic digestion into amido-acids. 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). 



