ON COLLOID CHEMISTRY AND ITS INDUSTRIAL APPLICATIONS, &7 
temperature it commences to coagulate and at 70° it is converted into a 
solid white gel. If, however, it is evaporated at temperatures below 40° 
it dries to form a paie yellow, transparent, brilliant film which is easily 
broken up into scales, in which form it is sold. " 
Salts, e.g. (NH,).SO,, lower the coagulation point of albumin. The 
effect is not so marked with egg albumin as with serum albumin, while 
milk albumin is much more sensitive (K. Micho, ‘ Zeitschr. Unters. Nahr. 
Genussm.’ 1911, 646-654). 
Dried albumin contains about 12 per cent. of moisture and 5 to 6 per 
cent. of mineral matter ; the alkalinity equals about 2-4 per cent. of NaHO, 
but on boiling with water the alkalinity is increased to 4-13 per cent. ; 
it would appear, therefore, that on coagulating a chemical change takes 
place. The alkalinity is probably due to phosphates. 
‘Albumin forms homogeneous systems with gum arabic and with agar. 
The specific gravity of ege-white is 1:045. Harriette Chick and C. J. 
Martin ( Zeitschr. Chem. Ind. Kolloide,’ 1913, 12, 69-71) found that 
the densities of ege albumin, crystalline serum albumin, serum globulin, &e., 
compared with the densities of the same products in the solid state, show 
that on dissolution there is a contraction amounting to from 5 to § per cent. 
It was also found that with serum albumin and serum globulin the solution 
volume was independent of the concentration, but that with casein the 
contraction which takes place diminishes with increasing concentration. 
Albumin adsorbs Ag,O from a solution of the nitrate, forming silver 
albuminate ; and it was found that in photography the whole of the silver 
was not removed from this compound after fixing with sodium thiosulphate 
(Luppo Cramer, ‘ Zeitschr. Chem. Ind. Kolloide,’ 1907, 2, 171-172). A 
compound of albumin and copper is also formed by adding CuSO, to a 
solution of albumen, with or without the addition of KHO. In the absence 
of alkali the product had an almost constant composition, the Cu and SO, 
being present in equivalent amounts, the product containing albumin 
86°67, Cu 5-26, and SO, 8-07. In presence of alkali the proportion of 
SO, in the compound decreased as the alkali was increased, until the 
product had the composition albumin 68-75, Cu 31-25 (G. Bonamartin and 
M. Lombardi, ‘ Zeitschr. Physiol. Chem.’ 1908, 58, 165-174). 
When aqueous sols of albumin, tannic acid, and a metallic salt, &c., are 
mixed, a precipitate is obtained which contains albumin, tannic acid, and 
the metal. Using 20 per cent. sols in all cases the precipitates had the 
following molecular composition calculating tannic acid as a dibasic acid 
Metal. Albumin. Tannin, 
Ag salt 4 18 32 50 
1h a , es (| 4) 46 
ET : 15 50 35 
JAC ae 10 48 42 
Ons 9 50 41 
Ph, 16 45 39 
ie, 5; 5 60 35 
Bro es ‘ j 15 21 64 
I phe 23 21 56 
G. Grasser, ‘ Colles’ 1911, 185-192 and 199-200. 
A compound or combination of chloroform with an albumin has. 
according to C. 8. Schleich (‘ Therapie der Gegenwart,’ 1909, 138), been 
prepared. This preparation, which has been named ‘ desalgin,’ containg 
25 per cent. of chloroform in a solid colloidal form, 
