90 REPORTS ON THE STATE OF SCIENCE.—1917. 
the acid (i.e, the H ion conc.). Acids are adsorbed by casein; thus 
from 100 c.c. of N/100 HCl nearly 50 per cent. was adsorbed in 3 hours ; 
the amount varies almost directly with the concentration of the acid. 
With 1 gram of casein the equilibrium ratios at 0° C. with N/500 solutions 
were H,SO, 675, HCl 147, lactic acid 80, acetic 30. The affinity of casein 
for acids is, however, less than that for bases ; 1 gram of casein combines 
with 9 c.c. of N/10 solutions of the hydroxides of Na,K,Li and NH, 
(F. Tangl, ‘ Pfliiger’s Archiv d. Physiol.’ 1908, 121, 534-549, ‘ Chem. 
Zeit.’ 1908, 1, 1288). 
Casein forms, with certain electrolytes, e.g., KI, NaCNS, Na,HPO,, 
and KNOs, fairly stable opalescent sols, which can be filtered ; these are 
precipitated on addition of acids. It is insoluble in pyridine, but in a solu- 
tion of pyridine it dissolves up to a maximum with increase of pyridine 
to C;H,N.H,O. It is almost insoluble in formamide (S. Levites, ‘ Zeitschr. 
Chem. Ind. Kolloide,’ 1910, 8, 4-8). Casein is rendered insoluble by 
formaldehyde. Tannic acid is absorbed by casein and can be quantita- 
tively estimated, although the results are 1 to 1-5 per cent. too high (M. 
Nierenstein, ‘ Chem. Zeit.’ 191], 35, 31). 
Casein is utilised in many different ways in industry. It is employed 
along with lime, with or without pigments, as a washable distemper ; 
as the lime carbonates it becomes insoluble. It is also used as a sizing 
material for textiles and paper (E. Sutermeister, ‘ Paper Making,’ 1914, 
33, 140-143), being dissolved by ammonia (T. J. Denne and A. Hentschel, 
Eng. Pat. 2,429, 1872) or borax (H. V. Dunham, USS. Pat. 897,885, 1908 ; 
see also F, W. Richardson, ‘ Jour..Soc. Dyers and Colourists,’ 1909, 25, 
4-3). Casein may be used as a cement along with sodium phosphate 
(W. A. Hall, Eng. Pat. 2,949, 1903), water glass (C. Wittkowsky, Eng. 
Pat. 9,070, 1905), slaked lime (C. W. Luther, Eng. Pat. 6,104, 1892), 
casein, rosin, and an alkali (C. and A. Bernstein, Ger. Pat. 270,200, 1913), 
sodium silicate and a strong solution of a salt of Ca, Ba, or Mg (A. Bernstein, 
Fr. Pat. 370,940, 1906). 
Casein is a useful material for the manufacture of plastic masses, 
which can be readily moulded and set hard after a time. ‘ Galalith,’ 
a combination of casein and formaldehyde, is a material of this kind which 
closely resembles bone or ivory and can be turned or carved (G. Bonitt, 
‘ Zeitschr. angew. Chem.’ 1914, 27, 2). 
Plastic masses can be formed by precipitating alkali-albuminate with 
acids and mixing the coagulum with a carbohydrate formed by the action 
of alkali solution on cellulose hydrate or starch, The mixture first liquefies 
and then progressively hardens (J. G. Jurgens and H. Timpke, Fr. Pat. 
420,164, 1890). Combinations of casein and amines, amides or their 
derivatives (e.g., aniline, acetanilide) are also employed (Soc. anon. 
L’Oyonnaxienne, Fr. Pat. 472,192, 1914). A substitute for horn or ivory 
is made from albumin or casein or alkali-albuminates by treating with 
the neutral esters of higher alcohols or amino-fatty acids which harden 
and coagulate them (W. Plinatus, Fr. Pat. 465,048, 1913). A mixture 
of casein and gelatin is treated with Na,SiO, and then hardened with alum 
(F. von Kagenek, Ger. Pat. 281,541, 1913). Hydrochloric acid forms 
a gel with casein which is plastic (Eborit. Ges.m.b.H., Ger. Pat. 191,125, 
1902). Casein is heated with water under pressure and the mass hardened 
with formaldehyde (Soc. anon. frang. de Chim. Ind., Fr. Pat. 425,204, 
1910). A combination of casein, gum, glue, and rosin oil is also similazly 
