51G SEDGWICK AND WINSLOW. BACILLUS OF TYPHOID FEVER. 
E. FATERIMENTS ON THE EFFECTS OF SEDIMENTATION AND CEYSTALLIZATION 
DURING THE FREEZING OF TYPHOID FEVEE BACILLI IN WATER. 
In tlie experiments under Section I, the reduction effected represented simply the 
doatli-r.ite amono!: the bacteria due to the adverse conditions. All the bacteria in the 
O 
unfrozen water which did not perish must, from the nature of the case, be present in 
the til awed ice. In nature, however, the conditions are widely different. Ice is 
formed immediately over and in immediate contact with a large body of water. In 
the water, before and during the process of freezing, the bacteria, being particles 
somewhat heavier than water, continually tend to settle out from the region where 
ice is to form and fall gradually to the bottom. And when the ice formation actually 
takes place, a still more powerful force comes into play. In the process of crystalli- 
zation there is a strong tendency to throw out all substances other than the pure 
compound chiefly concerned. If, then, soluble chemical compounds, other th 
hydrogen monoxide are excluded to a large extent when water freezes, this mi 
be still more the case with suspended particles like the bacteria. 
These a nt 
o 
d by the work of Pengra and of the 
o 
o 
Massachusetts State l^oard of Health as well as by common scientific knowled 
To test them more carefully with respect to Bacillus typhi abdominalis and Bacil- 
lus coli the following experiments were made. A new wine-cask, of about ten 
dlons capacity, was allowed to stand full of water for a few days in order to remove 
any extractives present. Four pet-cocks were then screwed in, on opposite sides 
of the cask, two about four inches from the top and the others an inch or so from 
the bottom. The whole cask was jacketed with felt so that when placed at a low 
temperature it would freeze from above down and not from the sides inward. It 
was then filled with water, at about the boiling-point, drawn from an ordinary water- 
heater. This water was then allowed to stand for twenty-four hours, when it was 
found cool and still very nearly sterile, containing three or four germs per cubic 
centuneter. The barrel of water was then inoculated by pouring into it a boui 
culture of the germ used, the conunon colon bacillus in the first four experiments 
the typhoid bacillus, Race B 
During the course of the exper 
no sterilization was attempted beyond that partially effected by the boil 
After adding the culture and stirring with a sterile rod, samples were taken from the 
four pet-cocks and planted. The covered cask was then set aside in the room or 
placed on a broad sill just outside the window of the laboratory, where it was exposed 
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