DAIR\ FARMING DAIRYING. 1019 



"Basic calcium casein and paracasein appear soluble in water forming slightly 

 opalescent solutions. Neither is coagulated by rennet, but both are precipitated by 

 soluble calcium salts on warming. Neutral calcium casein is coagulated by soluble 

 calcium salts on warming to 35 to 40° < .'.. butnotat ordinary room temperature, while 

 neutral calcium paracasein is completely and quickly coagulated at room tempera- 

 tures by soluble calcium salts. Free casein and free paracasein, freshly prepared. 

 possess the same solubilities in warm 5 per cent salt solution and in hot 50 per rent 

 alcohol; they also possess the same peculiar properties of plasticity and ductility. 

 The close resemblance of casein and its compounds respectively to paracasein and 

 its compounds suggests that they are chemically alike, paracasein being different 

 only by consisting of a larger molecular aggregation than casein. 



"Free paracasein appears to he identical in characteristic properties with the com- 

 pounds we formerly called paracasein mono-salts of acids used as precipitants. The 

 compounds which we have heretofore railed paracasein di-salts <>f acids appear to he 

 combinations of free paracasein and acids u .-ed as precipitants, 1 gram of para- 

 casein uniting, fm- example, with about 0.5 cc. of decinormal hydrochloric acid. 



" From water-extracted fresh Cheddar cheese we prepared one extract by warm 5 

 percent salt solution and another by hot 50 per cent alcohol. These preparation- 

 have in common with free paracasein the characteristic properties of plasticity, 

 ductility, and the same combining power with ha-es and acids, and therefore appear 

 to he free paracasein instead of paracasein mono-lactate as we were formerly led to 

 believe. 



"When an acid is formed iu or added to cows' milk, the acid tirst combines with 

 the bases of some of the inorganic salts of the milk and then with the calcium that 

 i> combined with the casein, resulting in the formation of a precipitate which is free 

 casein. By further formation or addition of acid, the free casein unites with acid. 

 forming a casein salt of the acid, this compound, in the case of lactic acid, heing the 

 coagulum familiar in the ordinary souring of milk. 



"The coagulum, following the addition of rennet enzym to milk is calcium para- 

 casein, either mixed or loosely combined with soluble calcium salts. While lactic 

 acid ir- being formed in the process of cheese-making, it combines with the calcium 

 of the calcium paracasein, forming free paracasein and calcium lactate. It is this 

 free paracasein thus formed that is soluble in warm 5 per cent salt solution and in 

 hot 50 per cent alcohol and possesses characteristic properties of plasticity anil 

 ductility. 



" Much confusion prevails at present in the use of the terms casein and paracasein. 

 It is suggested that the following nomenclature be used: il i That the compound 

 existing in cows' milk he called calcium casein. (2) That only the free proteid 

 be called casein. (3) That the casein compound containing L\40 per cent of cal- 

 cium oxid be called basic calcium casein. (4) That a compound formed by pre- 

 cipitation and combination with an acid be called a casein salt of the acid used, i 5 i 

 That the sam.- nomenclature he applied to the corresponding paracasein bodies, with 

 the following addition: Calcium paracasein should be applied to the uncoagulated 

 form and the term coagulated calcium paracasein to the coagulated form." 



Technical-bacteriological investigations in Emmenthal cheese making, 

 A. Peter (Landw. Jdhrb. Schweiz, in (1905), No. 5, pp. 171-181 >.— The rate of acid 

 formation in Emmenthal cheese and the use of natural rennet in comparison with 

 artificial rennet with and without the addition of pure cultures of lactic-acid bacteria 

 were studied under practical conditions. < )n an average of 11 tests the expressed 

 whey at the outset showed 4° Soxhlet, after 2 to 2\ hours ki.6°, and after 5 to 6 hours 

 45.3°. A rapid increase in acidity was favorable to the production of good cheese. 

 By the use of natural rennet, the desired acidity was secured better than when arti- 

 ficial rennet was used. An objection to the use of natural rennet is the frequent 

 occurrence in it of the gas-producing organism Bacterium coli communis and B. lactis 



