Xkw Yokk AraacuLxriiAL Expeki.aiext Station. 335 



lactic acid (1 gram of paracasein uniting supposedly with about 

 0.5 cc. Jo acid). It may be stated here, in passing, that it was later 

 shown by L. L. Van Slyke and D. D. Van Slyke^ that the protein 

 casein does not unite with acids to form insoluble compounds, but 

 that the action is simply one of adsorption, by which more or less 

 acid is taken from the surrounding solution and concentrated on 

 the surface of the solid particles of protein; in other words, it was 

 shown that casein or paracasein mono-lactate or di-lactate have no 

 existence as applied to the compounds in question. It still remained, 

 therefore, to find out what the brine-soluble substance really is, and 

 work was continued along this line by the writers.- We noticed 

 that calcium is always to be found associated with the brine-soluble 

 substance when it is separated from the other cheese constituents 

 by extraction with a solution of calcium-free sodium chloride after 

 previous removal of all water-soluble constituents. This fact sug- 

 gested the possibility that the brine-soluble substance might be a 

 combination of paracasein and calcium, containing less calcium than 

 had been previously found in any combination of this element with 

 paracasein. On the basis of such a possibility, it could be explained 

 that with the formation of increased amounts of lactic acid in cheese- 

 making, as a result of the bacterial decomposition of milk-sugar, 

 the acid would combine with more or less of the calcium contained 

 in calcium paracaseinate, resulting in the production of a para- 

 caseinate containing less calcium. This suggestion was strengthened 

 by the fact that in Camembert cheese, the brine-soluble compound 

 is formed during certain stages of the manufacturing process but 

 soon disappears, its formation and disappearance being explained 

 as follows according to Bosworth:^ The brine-soluble substance is at 

 first formed in Camembert cheese, as also in the case of cheddar 

 cheese, but, owing to the method of making this type of cheese, 

 more acid is allowed to form in the cheese, and, as a consequence, 

 the brine-soluble substance loses its calcium and becomes free para- 

 casein, which is insoluble in brine solution. Therefore, in the manu- 

 facture of Camembert cheese, it is found after the first few hours 

 that the cheese contains no brine-soluble material and, what is also 

 significant, all the calcium is found in the water extract. The rela- 

 tion between the brine-soluble substance and the calcium found in 

 the brine extract in the two tvpes of cheese is illustrated in 

 Table XV. 



The question necessarily suggests itself as to whether the calcium 

 always found in the brine-soluble extract of cheese is not there 

 incidentally in a mechanical state rather than in combination with 

 paracasein. In order to study this question the following work 



» N Y. Agr Exp. Sta. Tech. Bui. No. 3, 1906. 

 2 N. Y. Agr. Exp. Sta. Tech. Bui. No. 4, 1907. 

 » N. Y. Agr. Exp. Sta. Tech. Bui. No. 5, 1907. 



