FEBRUARY 9, 1912] 
tion kills the lactic acid organisms and leaves the 
spores of peptonizing and putrefying bacteria. 
In the United States, however, pasteurized market 
milk coagulated sooner than does certified milk 
and peptonization occurs more frequently in the 
best grades of raw milk than in pasteurized 
market milk. 
Tt can not he hoped that pasteurized dirty milk 
can be made as good as pasteurized clean milk, 
nor can a uniform product be expected as the 
result of pasteurization of market milk. While 
the higher grades of raw milk quite consistently 
have a low bacterial count, still they show a 
marked variation in flora. This same variation is 
observed in pasteurized market milk. 
The technique in the laboratory does not prevail 
in the dairy and while pasteurization in sealed 
bottles can be made to represent laboratory meth- 
ods, pressure for time may lead to over- or under- 
heating and shortening of the length of time of 
pasteurization. While heating to 140° F. for 
twenty minutes is sufficient in the laboratory to 
destroy pathogenic organisms, commercial condi- 
tions and mechanical devices are such that pas- 
teurization should be carried on at a higher tem- 
perature and for a longer period of time. 
The most efficient method of pasteurization is 
that under official supervision, controlling the 
quality of the milk pasteurized, pasteurization in 
the sealed bottle at 145° F. for thirty minutes, 
allowing at least thirty minutes to heat the milk 
to the pasteurizing temperature, and labeling such 
milk properly. This will insure sufficient tem- 
perature to destroy pathogenic bacteria, will in- 
activate the ferments but little, leave a good 
cream line and give a preferred milk. 
The Bacterial Content of Oysters in the Shell in 
Storage: G. W. STILEs. 
Samples of oysters in the shell were taken from 
known localities during the months of November, 
1910, and February, 1911, and placed in storage 
at a temperature of 39°F. Bacteriological an- 
alyses were made on five oysters constituting a 
single sample at various intervals ranging from 
one to 29 days. The usual technique for oyster 
work was observed for making the cultures. The 
oyster shells were well scrubbed in running tap 
water, their beaks briefly immersed in boiling 
water, and, with sterilized forceps and knife, the 
liquor removed from the shell into five sterilized 
petri dishes, one for the liquor of each oyster. 
Definite quantities of 1 ¢.c., 0.1 ¢.c. and 0.01 c.e. 
from each oyster were planted into Durham fer- 
SCIENCE 
235 
mentation tubes containing lactose peptone ox 
bile. Dilutions of one to one hundred, one to one 
thousand, one to ten thousand, ete., were planted 
in duplicate on agar plates and incubated at 
20° C., and 37° C., respectively, for three days. 
The results obtained from the fermentation tests 
were expressed according to the suggested score 
of the Committee on Standard Methods of Shellfish 
Examination (Journal of American Public Health 
Association, Vol. I., No. 8, August, 1911). 
Charts illustrating the B. coli content and the 
total bacterial count were exhibited. The results 
obtained varied, but not sufficiently to give posi- 
tive indications as to results which may be ob- 
tained with samples stored at higher degrees of 
temperature. The variation of individual samples 
not in storage may, under certain circumstances, 
be as great as the results obtained on those kept 
in storage. Additional work on oysters showing 
greater degrees of pollutions and during different 
seasons of the year are contemplated before final 
publication. 
Seasonal Variation in the Bacterial Content of 
Oysters: GEO. H. SmirH. 
During the sanitary survey of Narragansett Bay, 
carried on during 1910-11, several facts were 
brought out regarding the bacterial content of 
oysters during different seasons. Frequent exam- 
inations of several layings were made during the 
period from December, 1910, to May, 1911, that is, 
during the coldest part of the year and during the 
period of the warming of the water. In these 
examinations the total count of organisms in the 
shell-juice of the oyster and the sea-water, the 
presence or absence of the colon bacillus in the 
oysters and the sea-water, the temperature of the 
water, etc., were noted. 
An analysis of the data thus obtained seems to 
warrant the following statements: 
During the colder winter months both the total 
number of organisms and the number of B. colt 
present in the oyster are very low as compared 
with that of the warmer weather. 
The times when the total count and the colon 
count of the oysters are lowest are not the same, 
except within wide limits. 
The period when the oysters contain the lowest 
total number of organisms or the fewest B. colt 
is not the period of lowest temperature. 
The drop in total bacteria and in colon is ap- 
parently not related in any way to the decrease 
of organisms in the sea-water. 
Thus it appears that the decrease in the bac- 
