186 
TYPHOID FEVER IIs" DISTRICT OF COLUMBIA. 
The positive results reported by Field (1903-4) are of some value, 
as his identification of the organism isolated was complete, while the 
negative findings can not be given much weight, as no special means 
were employed to recover the B. typhosus. His results for oysters 
allowed to remain in infected sea water showed a viability of nine 
days in shell water and a negative result in fourteen days; for oysters 
placed in new sea water after infection, forty-eight hours, not longer; 
for sea water itself six to eight days. TFood and Klein unfortunately 
omit a description of their methods in such reports as we have been 
able to consult, but Wood (1896) gives a viability in imsterilized sea 
water of three months at various temperatures from 4° to 20° C. 
Klein (1905) reported that infected oysters kept in sea water con- 
stantly changed retained the bachlus six to seven days as a rule; 
kept dry, eleven days. Other shell fish retained it much longer. 
ViaMlity in dairy products . — The work of Bruck (1903) is of great 
interest in this connection. This observer followed in all his experi- 
ments conditions which obtain in the ordinarv handlinof of dairv 
products. He took ordinary milk from the dealers and infected it 
Avith B. typhosus. He then separated the cream in the centrifugal 
machine commonly used for that purpose and found that it con- 
tained the organism not only immediately after separation but con- 
tinued to do so for ten davs. Others have shown that centrifugation 
of milk does not precipitate all of the bacteria to the slime layer, but 
allows many to remain in the cream — more, even, than in the skim 
milk. (Bassenge.) From another portion of tliis cream he manu- 
factured butter, from which he could still obtain B. typhosus up to 
the twenty-seventh day, but not on the twenty-eighth or later. The 
buttermilk retained the bacillus only ten days. There even appeared 
to be some growth of the organism in butter for the first few davs. 
He then demonstrated that bv rinsing the churn with infected water 
the butter made therein could be infected, a fact which would hardly 
seem to call for proof. His methods throughout appear to be of the 
best. 
Pfuhl (1902) after inoculating imsterilized milk found that the 
bacillus was demonstrable after thirteen days, but does not state 
when negative results were obtained. In butter it lived twenty-four 
but not twenty-six days, and for Gervais cheese the same figures are 
given. 
Concerniug the viability in milk, raw and sterilized, much might be 
adduced, but it is well known that milk is ordinarily used long before 
any typhoid bacilli present would have died out. 
The limiting influence appears, according to Bassenge (1903) to 
be the acidity, which is fatal to the bacillus within twenty-foirr hours 
after reaching 0.3 to 0.4 per cent. 
