184 
O' Brien . — The Proteids of Wheat . 
II. 
My own observations on the proteids of flour may be 
described under the following headings : 
A. Action of water on flour. 
i. Globulins. 
ii. Proteose. 
iii. Gluten. 
Substances derived from gluten : zymom ; glian, including myxon, 
glutine, mucine. 
B. Action of solutions of salt (NaCl). 
C. Action of Alcohol. 
Albuminate. 
D. Relation between gluten and the albuminate. 
A. Action of Water on Flour . 
The addition to wheat-flour of about half its bulk of water 
causes, as is well known, the formation of a thick tenacious 
paste whose characteristic properties are due to gluten, a nitro- 
genous elastic substance in which the starch, cell-walls, and 
other parts of the inner endosperm of the wheat-grain are 
at first embedded. So coherent, however, is the gluten-mass 
that by prolonged washing in water these other substances 
may be almost entirely removed, crude gluten remaining 
behind. Fat and colouring-matter may be removed by 
ether ; but it is impossible to get rid of the last traces of 
starch. 
Gluten, however, does not constitute the whole of the 
nitrogenous matter of the flour ; the washings of gluten also 
give proteid reactions, and two kinds of proteid may be 
distinguished. When the slightly acid liquid thus obtained 
by washing is neutralised, no appreciable precipitate is 
formed : therefore no acid-albuminate is present. On boiling, 
however, coagulation occurs, indicating either globulin or 
albumin ; on removal of this by filtering, the solution still 
gives proteid reactions, so that a proteose or a peptone must 
also be present. As the whole of the proteid matter originally 
present in the washings is precipitated by saturation of the 
solution with magnesium sulphate, the presence of albumin and 
