442 
Journal of Agricultural Research 
Vol. XI, No. 9 
The actual checking of the increase in soluble nitrogen due to the 
addition of i per cent of sodium chlorid was approximately io per cent 
in either case, but 3 per cent of the salt did not entirely prevent proteo¬ 
lysis. 
(e) Occurrence of galactase in milk during process of butter 
making. —In following the protease of the fresh milk to the finished 
butter, the reaction of the various products was in every case brought 
to that of the fresh milk—that is, 10 c. c. were exactly neutralized by 
1.5 c. c. of Njio alkali when phenolphthalein was used as an indicator, 
by dipping a stick of sodium hydroxid into the sample. If the sample 
became too,alkaline, it was neutralized by some of the original sample 
so that dilution was avoided. The various samples were treated with 
chloroform in the following proportions: The skim milk, buttermilk, and 
bowl contents, 0.5 per cent; the milk, 2.5 per cent; and the cream, 
which contained 23 per cent of butter fat, 5 per cent. The “bowl con¬ 
tents” was an emulsion of the slime in the wash water held in the bowl. 
An equal volume of boiled skim milk was added as a substrate, but the 
increase in the soluble nitrogen was calculated on the basis of the bowl 
contents alone. The “cream during ripening” refers to the proteolysis 
occurring during the 10 hours it was ripened at 85° F. and the 20 hours 
it was held at 54 0 previous to churning. 
Table V .—Presence and concentration of galactase in milk and. butter as indicated by the 
increase of soluble nitrogen 
Sample. 
Total 
nitrogen. 
Initial 
soluble 
nitrogen. 
Soluble 
nitrogen 
after 
4 days. 
Increase. 
Initial 
percentage 
of total 
nitrogen 
as casein. 
Skim milk . 
Whole milk. 
Cream. 
Bowl contents. 
Cream during ripening. .. 
Cream after ripening. 
Buttermilk. 
Per cent. 
O. 0583 
.0544 
. 0403 
. 0189 
. 0403 
. 0403 
•0551 
Per cent. 
O. 0129 
• OI13 
. 0076 
. OO46 
. 0076 
. 0081 
. 0125 
Per cent. 
0. 0183 
. 0198 
. 0142 
. 0262 
. 0081 
.0139 
. 0201 
Per cent. 
II. IO 
IK. 62 
16.37 
114. 28 
1. 66 
14 . 39 
13. 60 
77.87 
79 - 2 3 
8l. 14 
89-93 
It appears from these data that in separating milk, galactase is taken 
out of the skim milk part, slightly increased in the cream, and highly 
concentrated in the separator slime. While no relationship exists be¬ 
tween the increase in soluble nitrogen and the total nitrogen, it is evident 
that the factors at work during milk separation which increase the per¬ 
centage of casein in the total nitrogen also increase the galactase con¬ 
tent. The cream underwent a slight proteolytic digestion during the 
ripening process, but the proteolysis after souring and neutralization 
was less than that of the sweet cream. This indicates that the chief 
