New YorK AGRICULTURAL EXPERIMENT STATION. 191 
ing in its place hydrochloric acid, added in small quantities from 
time tu time, both before and after the addition of rennet. Para- 
casein chloride was readily formed by the curd, but the use of 
somewhat too much acid produced an abnormally large propor- 
tion of the unsaturated salt, which, on addition of common salt, 
formed a mushy, slippery mass. The curd, in this condition, was 
suspended in water and more hydrochloric acid was added, result- 
ing in the production of a firm, exceedingly hard curd, due to 
the conversion of unsaturated into saturated paracasein chloride, 
the latter compound not being soluble in salt-solution. 
(4) Amount of unsaturated paracasein lactate in newly-made 
cheese.— In new cheese, fresh from press, prepared under normal 
conditions, we have found as much as 78.5 per ct. of the nitro- 
gen-compounds present in the form of unsaturated paracasein 
lactate. The proportions of this compound in new cheese depend 
upon a variety of conditions, which we are engaged in studying. 
It appears probable that, in the case of normal, newly-made 
cheese, the nitrogen-compounds consist mainly of unchanged 
paracasein and unsaturated paracasein lactate, the latter com- 
pound being present in large proportions. Saturated paracasein 
lactate probably does not occur in normal cheese, but only in 
cheese made with excessive acid, as, for instance, cheese made 
from sour milk. 
RELATION OF UNSATURATED PARACASEIN LACTATE TO CHEESE-RIPENING. 
As cheese ages, it undergoes various changes, passing frum 
an insoluble and flavorless substance into the palatable, more 
easily digestible, and nutritious material we use as food. The 
term “ripening” is applied to the general process that embraces 
these changes. Among the most extensive and profound changes 
occurring in cheese-ripening are those experienced by the nitro- 
gen-compounds of the newly-made cheese, chief of which is unsat- 
urated paracasein lactate. 
A large amount of bacteriological and chemical work has been 
done in order to ascertain the cause of the changes that occur in 
the nitrogen-compounds during the ripening of cheese. All of 
