48 Report OF DEPARTMENT OF BACTERIOLOGY OF THE 
\ 
vegetative forms is measurable. With 1.0 per ct. of chloro- 
form the case is somewhat different, since vegetative forms per- 
sist for many hours. 
Since many of the forms present were lactic germs, a sensitive 
test of their activity was the reaction of the milk. Accordingly, 
at the end of 25 days the milk was titrated, using phenol- 
phthalein and decinormal sodium hydroxide. The bottles con- - 
taining 1.0 per ct. of chloroform showed an acidity equal to 
25.6cc. of normal acid to the litre; with 1.5 per ct. chloroform, 
an acidity of 22.8cc.; and with 2.0 and 2.5 per ct., an acidity of 
2Icc. of normal acid to the litre. While these differences are 
slight, they are suggestive that, so long as vegetative forms are 
present, there may be a minimum amount of bacterial action in 
the presence of an amount of chloroform which is producing a 
constant diminution of the germ content. 
EFFECT OF PROTEIDS AND FAT IN’ CHEESE; 
It was shown on page 40 that the presence of 3 per ct. of 
proteids prevented the germicidal action of 0.3 per ct. of chlo- 
roform, and on page 43 that the presence of 5 per ct. of fat 
rendered 1.0 per ct. of chloroform inactive. In average green 
cheddar cheese we have approximately 24 per ct. of proteid 
and 34 per ct. of fat, so that the need of a considerable per- 
centage of chloroform in order to prevent germ action is evident. 
Calculated on the basis of the above results, the proteid should 
absorb 2.4 per ct. and the fat 6.8 per ct. of chloroform by 
volume. In the case of cheese, it is manifestly more convenient 
to handle percentages by weight than by volume and the above, 
expressed as percentages by weight, would be 3.55 per ct. and 
10.06 per ct. respectively. It should be noted that the change 
which takes place in the physical condition of the proteid in 
passing from milk to cheese is so great that these values may be 
subject to wide variations. ‘That these figures are too high is 
rendered more than probable by the results given on page 59, 
where it was shown that 3 per ct. of proteid and 20 per ct. of fat 
was protected by 2.5 per ct. of chloro tony when 4.4 per ct. was 
indicated by these figures. 
In preparing chloroformed cheese, the chloroform was added 
to the milk and the ordinary operations of cheese-making carried 
out as usual. The milk used-was of the quality ordinarily used ~ 
for cheese-making, except that used in cheese 6.2, which had been 
