BACTERIA IN THE DAIRY. 59 
cultivated solely in the writer’s bacteriological laboratory and 
upon ordinary culture media. 
When experiments in the creamery or elsewhere are desired, 
the procedure is as follows: ‘There is first placed in an ordinary 
flask a half pint of milk, and this is sterilized by discontinuous 
steaming for three or four successive days. This sterilized milk 
is inoculated with a small amount of the Bacillus No. ar, and the 
culture thus made is allowed to grow at about 23° C. (74° F.) 
for a couple of days. The object of this growth is merely to 
increase the number of bacteria and thus make a larger inoculation 
in the creamery possible. After two days’ growth the culture 
is sent to the creamery and the rest of the experiment is performed 
there by the butter-maker. 
A lot of cream, amounting to six or eight quarts, is placed in a 
metal vessel and pasteurized, by being put into a tub of water 
into which steam is allowed to run. The temperature of the 
cream is allowed to rise to about 69° C. (156° F.) and to remain 
there for some ten minutes. The cream vessel is then removed 
and placed in cold water and cooled as rapidly as possible. 
When the temperature has fallen to about 23° C. (74° F.) the 
milk culture of the bacillus above described is poured into it 
and is thoroughly mixed with it by stirring. The vessel is then 
covered and placed in the ripening room of the creamery for 
two days, at the end of which time the cream is churned 
and the buttermilk reserved for further use. The object of this 
ripening of a lot of six quarts of cream is to increase the num- 
ber of bacteria in order that a large and strong culture may be 
obtained for use in the large vat of cream in the creamery... The 
buttermilk from the churning of the six quarts of cream is then 
inoculated into the day’s cream as soon as the cream is placed 
in the vat for ripening. The cream in the large vat receives 
no preliminary treatment, the prepared milk being poured into 
it directly. The cream is then allowed to ripen at a normal 
temperature for about twenty-four hours and churned as usual. 
Before the churning two or three gallons of the ripened cream 
is set aside to be added to the next day’s cream collection to 
insure a continuation of the process. In this way the ripening 
is continued day after day, a small amount of each day’s churning 
being set aside for the next day’s inoculation, and the process is 
continued as long as the good effects of the original culture are 
seen. Inthe series of experiments which were instituted it was 
‘ 
