O'Brien. — The Proteids of Wheat . 179 
whilst as regards solubility in dilute acids I shall show that 
this is not great in the alcohol-soluble proteids. 
In one or two physical points, moreover, myxon behaves 
somewhat like the casein of milk,; which may more readily 
than fibrin be made to dissolve in part in dilute alcohol, and 
which forms a skin on the exposed surface of a solution 
cooling in the air. So characteristic of Ritthausen’s gluten- 
fibrin (myxon) is such skin-formation that it is used to 
distinguish it from gliadin and mucedin. 
A full account is given of the preparation and of the 
properties of these four substances : I can only point out that 
they are by no means sharply marked off from each other. 
Thus myxon is soluble in alcohol 80-90% in the cold, in 
alcohol 30-70% only on heating. Gliadin [glutine] is most 
soluble in alcohol 70-75% and is slightly soluble in water ; 
mucedin is somewhat more soluble in water, but is precipitated 
in the cold by 90-95% alcohol. In chemical composition 
zymom is hardly distinguishable from mucedin ; as regards 
solubility they are at the extremes of the series. The 
proportion in which these bodies occur is said to vary in the 
gluten of different wheats : and no estimate is given beyond 
an instance in which zymom formed 2 8% of the dry weight of 
gluten. Gliadin [glutine] is specially variable — on it is said 
to depend the tenacity and elasticity of gluten. 
While these investigators were thus elaborating the know- 
ledge of the constituents of gluten and the composition of 
particular proteids, others were determining the more general 
characters of proteid bodies and their relation to each other. 
Denis 12 as early as 1840 had found the value of neutral salts 
in the separation of proteids. Though his special work was on 
the blood 17 , yet he described a substance found in peas, beans, 
almonds and wheat, soluble in dilute solution of sodium 
chloride, and precipitated from it by excess. This he named 
‘glutine,’ believing that there was one vegetable proteid 
which appeared under the varying forms of legumin, amandin, 
gluten, vegetable albumin, casein and fibrin. 
Kiihne 20 (1864) investigated the composition of animal 
