118 CASEIN. 



hydrochloric acid, though reprecipitated on the amount of 

 acid being still further increased. 



Casein solutions are also precipitated by the action of the 

 mucous membrane of the stomach of the calf, and also by 

 the gastric juice' of carnivorous animals. Precipitation is 

 also produced by tannic acid and metallic salts, and a parallel 

 to the behaviour of alkaline solutions of casein is also ex- 

 hibited by the natural solutions of the substance, as in milk. 



CASEOGUM 



is a solution of casein in lime-water, and is used as an 

 adhesive, more particularly for impregnating cotton and 

 linen fabrics, which, on exposure to the air, absorb carbon 

 dioxide. The casein, which is deposited on the fibre,- assists 

 the latter to absorb dyestuffs. 



Thirty-two parts of fresh curd are stirred with 48 parts 

 of water at 64 F. and rubbed through a metal sieve in order 

 to reduce it to a finer state of division. On the other hand, 

 | part of fresh, well-burned lime is slaked gradually with 

 warm water until it falls to powder, which is thereupon 

 mixed with 3| parts of warm water, triturated, filtered 

 through paper, and gradually added to the curd by stirring. 

 The mixture at first thickens, and it is only after prolonged 

 stirring that it grows thinner and attains the desired con- 

 sistency. Care must be taken to have fresh lime of good 

 quality, and to slake it with just the right quantity of water ; 

 neither too much nor too little. The curd must be rubbed 

 down fine with the water so as to eradicate all lumps, and 

 the water must be at the temperature already specified. 



" GLUTIN." 



" Glutin " is a glaze for dressing curtain fabrics, and is 

 also used as a medium for colours in dyeing and calico print- 

 ing. It is prepared as follows : 



Curd, freed from adherent moisture by pressure, is ground 



