O'Brien. — The Proteids of Wheat. 183 
fermentation. Mercuric chloride fixes the proteid of flour and 
so prevents gluten-formation, whilst it is promoted in poor 
flour or even in barley-meal by the addition of a small 
quantity of good flour. 
Martin 35 (1886) at once supports the ferment-theory, and, 
following up Weyl’s researches, tries to bring the proteids 
of wheat into line, with the more typical proteids — two 
propositions which are by no means dependent on each 
other. Finding in an extract of flour made with water or 
io°/ o salt-solution, (1) an albumose, (2) myosin, he considers 
these as the precursors respectively of (1) the insoluble 
phytalbumose (glian) and (2) the fibrin (myxon), which to- 
gether constitute gluten. The two latter substances differ 
from the former in their insolubility in cold water and salt- 
solutions, and the solubility in alcohol acquired by the 
albumose. 
Balland’s 32 long series of observations (1883-93) on wheat- 
flour gives results differing from many of those used in 
support of the ferment-theory. Thus he finds that gluten 
may be made from flour which has been kept for some time 
at 8o° or even at ioo°C. ; that it may be obtained at 2°C. from 
flour previously kept at -8°C. ; and that its formation is in 
some cases actually promoted by the use of salt-solutions. 
He concludes his last paper, written in 1893 42 , with the 
words : Le gluten preexiste dans le ble. 
The opinion current among practical bakers may be 
gathered from the statement of Jago 34 , that gluten exists in 
flour as a fine powder, swelling up on addition of water into 
the well-known tenacious mass. 
On the one hand, therefore, is the theory of gluten-formation 
by ferment-action, supported by Weyl and Bischoff, Kjeldahl 
and Martin : on the other hand, the pre-existence of gluten in 
flour is maintained, on apparently sufficient grounds, by 
Johanssen and Balland. The question, then, of the origin 
and formation of gluten, like that of the nature of its proteids, 
is one which has not yet received a final answer. 
