92 REPORTS ON THE STATE OF SCIENCE.—1917. 
According to J. B. Wood (‘ Jour. Agric. Science,’ 1907, 2, 267-277), 
the properties of gluten are influenced by acids, by alkalies, and by salts. 
For instance, with HCl of N/100 strength it loses its coherence and 
commences to disintegrate, this effect increases with the concentration 
up to N/30, above which the opposite effect is noted, until with N/12 
acid it becomes permanently coherent, less sticky, harder, and more 
elastic. Similar effects are noted with H,SO,, H,;PO, and H,C,0O,, 
but acetic, lactic, citric, and tartaric acids, irrespective of concentration, 
produce only loss of coherence with no subsequent recovery of strength. 
Soluble salts induce greater coherence with weak solutions of HCl, sodium 
sulphate acting more strongly than NaCl and Mg and Al sulphates still 
more so. Alkalies cause the gluten to become negatively charged, while 
acids have the opposite effect. Long-continued washing with water 
causes the dispersion of the gluten, owing to the CO, which it contains 
(J. B. Wood and W. B. Hardy, ‘Proc. Roy. Soc.’ 1909, B. 81, 
38-43). 
When moist gluten is placed in a solution of a salt, the salt is adsorbed 
by the gluten and at the same time water passes into the solution, the 
result being partial dehydration. The most active in this respect are 
the sulphates; chlorides and nitrates being apparently equal. Salts 
of the alkalies are more active than those of the alkaline earths. The 
‘ partition constants’ of MgSO, and (NH,),SO,, both of which are used 
as protein precipitants, are stated to be considerable (A. J. J. Vandervelde 
and L. Bosmans, ‘ Bull. Soc. Chim. Belg.’ 1912, 26, 249-254). 
When gluten is bleached by SO, its elasticity is destroyed (M. G. 
Carteret, ‘ Bull. Soc. Chim.’ 1909, 5, 270-272). SO, gas has been proposed 
as a solvent for gluten in the preparation of an adhesive(E. Donath, Ger. Pat. 
172,610, 1905). Gluten is also brought into solution by means of a per- salt 
of an alkali (Erste Triester Reisschal-Fabriks Aktien-Ges. Trieste, Eng. Pat. 
8,203, 1910). 
A patent has been granted to G. von Riegler (Fr. Pat. 461,131, 1913) for 
the preparation of artificial milk by dissolving gluten in KHO, salts, &c. 
Soya beans (Soya hispida) contain about 38 per cent. of a proteid which 
resembles casein or gluten in its properties. In Japan and China it is the 
basis of several kinds of food, and it is also interesting, because it has been 
used more or less successfully in the manufacture of artificial milk, being 
converted into a colloidal solution by means of the phosphates of potash or 
soda and water and then emulsified with oil and lactose (F. Gassel, Fr. Pat. 
451,447, 1912, Eng. Pat. 27,860, 1912, also J. Monahan and C. J. Pope, 
U.S. Pat. 1,104, 376, 1914) ; it has also been proposed as a plastic material, 
for the manufacture of artificial horn, bone, &c., for which purpose it is 
boiled with water and then coagulated with Al,(SO,);, or formaldehyde 
(R. Dodd and H. B. P. Humphries, Eng. Pat. 15,316, 1913). 
Gelatin or Glutin. 
Gelatin is the most typical of the reversible colloids, a solution con- 
taining it being very fluid when hot, but setting to a clear stiff gel on 
cooling, which again becomes fluid at a temperature of about 25°C. Dry 
gelatin imbibes a certain amount of water in the cold,the quantity depending 
upon, and is used a test for, the quality of the material, but it retains its 
shape and does not dissolve unless it is very impure. In the case of glue 
