New York AGRICULTURAL EXPERIMENT STATION. 283 
that is, the form characterized by light-colored streaks, waves 
or large patches. It should be stated that Doane in the bulletin 
already referred to considered the relation of casein (casein 
lactate) to mottled butter but concluded that this proteid had no 
relation to the light-colored streaks of mottled butter. 
- Storch’ appears to attribute the formation of motties to an 
excessively large number of minute liquid drops of what he calls 
“watery mucoid substance,” the difference in the size and num- 
ber of these liquid drops being caused by the action of special 
micro-organisms during the ripening of cream. This theory lacks 
satisfactory demonstration and has not been received with favor. 
GENERAL METHOD USED IN MAKING BUTTER IN EXPERIMENTS. 
Before giving the detailed results of our work, we will give an 
outline of the method employed in making the butter used in our 
experiments. In carrying on some of the practical details of this 
work, we are indebted for codperation to Mr. Geo. A. Smith, 
Dairy Expert. The ‘butter-making was carried on as follows, 
except when otherwise specified in individual experiments :— 
The cream was pasteurized and contained 28 to 30 per ct. of 
fat. A carefully prepared starter was used in ripening the cream, 
the degree of acidity being made to vary in different experiments, 
but in most cases amounting to 0.6 to 0.7 per cent. The tem- 
perature of churning was commonly at 50° to 55° F. The churn- 
ing was stopped when the granules were about the size of grains 
of rice, except in those cases where the churning was purposely 
carried beyond this point. After the buttermilk was removed 
from the granules, they were treated twice with water at 40° to 
45° F., being allowed to drain well after each washing. We 
were careful to keep the temperature of the granules down dur- 
ing the washing so that they would not adhere and form lumps 
but retain their individuality. The completeness of washing the 
granules can be effected by adding the water in the churn and 
giving the churn a few revolutions. For conditions of normal 
work we took pains to remove the buttermilk as completely as 
possible from the granules. The butter was then salted at the 
rate of one ounce of salt for one pound of butter, and worked at 
once in some cases or allowed in others to stand a varying length 
1The Analyst, 22:206-7 (1897). 
