266 REPoRT OF THE CHEMIST OF THE ~ 
paracasein are both coagulated when warmed to 35° to 45° C. in 
the presence of soluble calcium salts, but not in the absence of 
soluble calcium salts. ! 
(5) Neutral calcium casein (present in milk) is coagulated by 
a few drops of a soluble calcium salt on warming; and neutral 
calcium paracasein (present in milk acted upon by rennet enzym) 
is coagulated at ordinary temperatures by soluble calcium salts. 
Neither neutral calcium casein nor neutral calcium paracasein is 
coagulated by rennet in the absence of soluble calcium salts. 
(6) Neutral calcium casein, prepared by making a lime-water 
solution of free casein neutral to litmus, is an opalescent solu- 
tion, free from any visible suspended particles; neutral calcium 
paracasein, prepared by making a lime-water solution of free para 
casein neutral to litmus, is a clearly defined coagulunr. In this 
respect only does there appear to be any marked difference in the 
behavior of the neutral calcium compounds of casein and para- 
casein. Here the difference is one rather of degree than of kind, 
since neutral calcium casein is coagulated by small amounts | 
of soluble calcium salts on warming, while neutral calcium para- 
casein is coagulated at lower temperatures by soluble calcium 
salts. 
THE RELATION OF THE SALT-SOLUBLE PRODUCT IN 
CHEESE TO PARACASEIN. 
It was from our work with cheese (American cheddar) that 
we gained the first suggestion which led us to investigate this 
field. It is desirable, therefore, that we should now, if possible, 
establish the relation between the salt-soluble, alcohol-soluble 
body obtained from cheese, which we were first led to regard 
as paracasein monolactate and the paracasein compounds we have 
prepared from milk and discussed in the preceding pages. 
We have established the fact that fresh cheddar cheese con- 
tains a large percentage of its proteid in the form of a body solu- 
ble in warm five per ct. salt solution and in hot 50 per ct. alco- 
hol. Weidmann*! dissolved from emmenthaler cheese by hot 
alcohol a substance called by him caseoglutin. Rése and 
Schulze?? made a quite extensive study of the properties of this 
* Landwirtsch. Jahrb., 1882, p. 587. 
* Landwirth. Versuchs-Sta., 31:130 (1884-5). 
