102 CASEIN. 



about two atmospheres. Here the sheets remain for about ten 

 hours, and, after being dried, are ready for use. 



By regulating the gas flames the heating can be adjusted 

 and kept uniform ; on no account should the metal be heated 

 to redness. The temperature is regul'ated by the melting 

 point of metallic alloys. The mould and cover are placed 

 empty in the press and heated ; and the interior of the 

 mould being carefully greased or oiled, the necessary 

 quantity of material is inserted, the cover put on and the 

 pressure gradually applied. The press attendant requires 

 to be skilled, in order to judge correctly when to stop press- 

 ing and take the plate out of the mould. When sufficiently 

 pressed, the plates are removed into a moderately warm room 

 to complete the drying. 



The finished mass is very hard ; so much so that it will 

 not break when thrown down on a stone floor. It can be 

 turned in the lathe, like real bone, takes a beautiful polish, 

 and is capable of numerous applications. 



PLASTIC MASS OF KERATIN AND CASEIN. 



Substances containing keratin are dissolved in alkalies or 

 alkali sulphides, along with casein, colouring matters, and 

 the like. The keratin is thrown down from the solution by 

 mineral acids and tannic acid, and the resulting mass is put 

 into moulds, pressed and dried. 



INSULATING MASS. 



This mass consists of a mixture of skim -milk casein and 

 a solution of resins (preferably mastic or sandarach, with a 

 little amber) in alcohol or turps (German patent 106,466). 



PLASTIC CASEIN MASSES. 



Dissolved casein is mixed with a solution of resin, the 

 mixture being incorporated with vegetable or mineral in- 

 gredients, and treated with formalin to coagulate the casein. 



