THE PREPARATION OF PLASTIC MASSES FROM CASEIN. 109 



a transparent product, aluminium caseate is the most suitable 

 adjunct ; zinc or magnesium caseate for a white product, and 

 the corresponding compound of manganese, iron, copper or 

 nickel for coloured articles. The caseate must be repeatedly 

 and carefully washed, from 1 to 5 per cent, of borax being 

 added towards the end of the process, to make the mass 

 more plastic and facilitate mixing with the other ingredients. 



PLASTIC MASS WITH A CASEIN BASIS. 



Jannin claims for the plastic mass prepared in the follow- 

 ing manner that it will replace celluloid and caoutchouc for 

 many purposes, being very solid, and at the same time easy 

 to cut, saw, turn and work in various ways without splitting 

 or cracking, besides being uninflammable, a good electrical in- 

 sulator, and capable of resisting the action of chemical reagents. 

 In principle, the method consists in mixing casein with some 

 fibrous material like cotton or wool cut into short lengths, in 

 order to render the casein less brittle and enable it to be worked 

 without splitting, the proportion of fibrous material used 

 varying according to the degree of strength and translucency 

 or opacity desired. A certain quantity of oil or other fatty 

 matter, glycerine, etc., is also desirable, but not essential. The 

 following proportions may be regarded as typical : Water, 100 

 parts ; alkali, 5 ; fibrous material, 10 to 50 ; oil or fatty matter, 

 10 ; casein, 100 ; colour, ad lib. The water and alkali are 

 mixed, and the colouring matter if any. The finely divided 

 fibrous material is then stirred in, followed* by the oil and 

 casein in succession, the mixture being stirred and heated to 

 dissolve the latter. The pasty mass is rolled to complete the 

 mixing and express imprisoned air, and is then moulded into 

 blocks, rolled into sheets or formed into any desired shape. 

 Formol or other tanning ingredient may be added. 



GALALITH. 



Galalith is the name given to a plastic mass which finds 

 a large number of practical applications in a variety of forms 



