192 O'Brien . — The Proteids of Wheat. 
relative accuracy of this is confirmed by adding the amount 
of zymom (28-3) and glian (1,5-32) obtained from moist gluten : 
they give 43*6°/ o for the dry weight. Probably not more 
than 40°/ o is pure gluten, for further loss of water may be 
effected by drying in a finely powdered state ; and starch 
and other impurities are present. It may be dried at ioo° C, 
and be kept for months without losing its power of becoming 
tough and elastic with water — as I found contrary to what 
is frequently stated. On dehydration with absolute alcohol 
it becomes a white powdery mass, which resumes the topical 
characteristics of gluten on being moistened. 
The solubility of gluten has been fully described by Ritt- 
hausen. It is soluble in dilute acids and alkalies — but for 
complete solution especially in acids I found that considerable 
time was needed even at ordinary temperatures : at the low 
temperatures employed by Ritthausen it seems to have taken 
place fairly readily. I found that gluten, though less readily 
soluble in sulphuric than in other acids, was ultimately 
attacked by it. A *5°/ o solution of sodium carbonate acts 
so slowly that one can use it for making the paste and also 
for washing for some time before the gluten is attacked. 
In water, gluten is insoluble — as one would expect from its 
mode of preparation : all the proteid soluble at ordinary tem- 
peratures being removed by the water used in washing. The 
same is true for a solution of sodium chloride. The fact 
that water in which gluten has stood for three or four days 
gives an albumose reaction simply indicates the gradual 
formation of this from gluten. 
In boiling water, however, gluten is to some extent soluble ; 
as pointed out by Giinsberg 19 and by Martin 35 . The latter 
describes the part soluble in boiling water as ‘ insoluble phyt- 
albumose/ and makes it coincide with the part of gluten 
soluble in alcohol [glian]. According to Giinsberg, however, 
although the part soluble in water is completely soluble 
in alcohol, the converse is not true. This I likewise find to 
be the case : and it may be proved in the three following ways. 
(1) If the clear alcohol-extract of gluten [glian] be poured 
