56 Report OF DEPARTMENT OF BACTERIOLOGY OF THE 
-renders it less efficient as a grinding medium in the case of new 
cheese which is both very tough and high in moisture. Here the 
quartz is decidedly preferable. As the cheese becomes older it 
softens and then can be. ground much better with sugar than with 
quartz. Care was taken to have the room in which the work was 
done as free from dust as possible and all utensils coming in con- 
tact with the cheese were either sterilized in the ordinary way or 
their surfaces were carefully flamed over a bunsen burner. There 
remains the objection that the material was exposed to the air for 
some minutes during the weighing and grinding. At most, the 
germs falling from the air were not numerous and with the high 
dilution necessitated by the germ content of the cheese there was 
slight chance of more than a single germ from the air appearing on 
any of the plates. In selecting colonies for further study only those 
were taken which represented two or more colonies on the plate. 
Thus we ifeel fairly certain that the germs to be later described 
represent forms which were present in the cheese when the sample 
was taken. 
It is a matter of common observation that cheeses which are 
sampled often do not ripen normally, due largely to the loss of mois- 
ture and the introduction of molds. Our method of overcoming 
this objection to frequent sampling was to fill the place from which 
the plug had just been taken with melted paraffin. While the heat 
from this paraffin slightly affected the texture of the cheese at the 
surface of the hole, plugs later drawn from the immediate vicinity 
showed no bad effects either in texture or flavor. The paraffin en- 
tirely prevented the entrance of molds. | 
DILUTIONS. 
The sample of freshly ground cheese was diluted with 30 cc. of 
sterile distilled water. This water was added gradually toward the 
close of the grinding process and the aim was to form an emulsion. 
The success in making a good emulsion varied with the age of the 
cheese, it being difficult to produce with a young cheese and easy 
with an old one. A measured amount of the emulsion was quickly 
transferred to a water blank from which the desired dilution was 
prepared. 
In calculating the dilution of cheese sampled in this manner two 
methods are in use. According to one method the dilution is com- 
puted ‘solely on the basis of the volume of water added in the 
grinding process while according to the other the proportionate 
