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CASEIN. 



caustic alkali (potash, soda or lime) or a carbonate, silicate- 

 borate or phosphate of soda or potash. The inventor states 

 that when an excess of alkali is present the product soon 

 becomes insoluble in water at the ordinary temperature. 

 On the other hand, when the albuminoid substance is in 

 excess the conversion proceeds slowly, but is accelerated by 

 warmth. In using the latter preparation, the surfaces to be 

 joined are coated with the mixture, left to dry, and then 

 pressed together between hot rollers. Inert substances may 

 be added to the mixture. 



LIQUID CASEIN GLUE. 



To prepare a stable casein glue, which will dry or set 

 immediately and perfectly resist moisture and the influence 

 of weather, 10 parts by weight of fresh curd are mixed with 

 6 parts of water to a thick pap, warmed to 40 C. and then 

 stirred with a sufficiency of ammonia until the casein is fully 

 precipitated. This furnishes pure casein, and the whey can 

 be eliminated by draining, pressure or centrifugalising. The 

 resulting casein . is washed by spreading it out on a stretched 

 cloth and pouring water over it. 



The product is next mixed with f to 1 part by weight of 

 strong ammonia solution in a pan and heated to 30 to 40 

 C., whereby it is converted into a liquid glue, which can be 

 diluted with about 80 per cent, of water and preserved by an 

 addition of carbolic acid or thymol. 



To make a quick-setting joint with this preparation, it is 

 laid on with a brush, and left to dry, the surfaces being after- 

 wards brushed over with milk (or thin cream) of lime and 

 pressed together. The calcium of the milk of lime combines 

 in the joint with the casein of the glue, ammonia being 

 liberated, and the resulting calcium caseate fixes the sur- 

 faces so tightly that the joined article can be worked five 

 minutes afterwards. 



