VARIOUS METHODS OF PREPARING CASEIN. 29 



used in America, and furnishes a light, dry, porous product. 

 Although similar methods have been employed in Germany 

 for some years, the inventor obtained a patent in that country, 

 the specification of which reads as follows : " A process for 

 preparing milk casein in a light, dry, porous form, consisting 

 in distributing a dilute aqueous solution of casein in a uniform 

 thin layer over a suitable surface previously heated to over 

 200 F., whereby the casein is dried, the operation being per- 

 formed under ordinary atmospheric pressure ". The following 

 modification is also described in the specification, but is not 

 protected by the patent : Twenty-five gallons of water heated 

 to 105 to 110 F. and containing 1 to 1| Ib. of carbonate of 

 soda in solution, are used to dissolve 175 Ib. of moist casein 

 or 119 Ib. of dry casein, with continued stirring. Two 

 metal cylinders, mounted so close together that nothing 

 thicker than a strip of paper can pass between them, are 

 rotated in opposite directions and heated by steam at a tem- 

 perature of 212 to 220 F., and the dissolved casein is allowed 

 to flow down between them. The liquid dries immediately, 

 and the thin, brittle layer of dried material is scraped or 

 brushed otf the rollers, whilst, if pressed through a hair 

 sieve, it furnishes a fine, soluble casein powder. 



This method is at all events cheap and simple, giving 

 a good, staple product, provided the fat and milk sugar have 

 been properly eliminated. The granting of the German patent 

 took two years, a sign of the tenacity with which the inven- 

 tor fought his case, though such a claim as that set forth 

 above is very little protection, and it is difficult to see where 

 the novelty comes in. 



According to a written communication from the inventor, 

 the process has been worked in America on a large scale since 

 March ; 1903, one factory treating 260,000 Ib. of skim milk 

 daily, whilst a second factory began operations in October, 

 1903 



