Tue INFLUENCE OF Low TEMPERATURE ON Sort BAacTERIA 1045 
freezing and thawing, and noted that it was only slightly more harmful 
than continued freezing. Park (1901), in working with the same organ- 
ism, found that all the bacteria were killed when embedded in ice for 
twenty-two weeks. 
Macfadyen (1900) exposed bacteria to the temperature of liquefied 
air for twenty hours without its affecting their vital properties. The 
yeast-cell plasma also retained its peculiar properties to effect the pro- 
duction of carbon dioxide and alcohol. In a later report (1903) Mac- 
fadyen gives results from using liquid hydrogen, the temperature of this 
being —252° C. No appreciable effect on the bacteria was noted.. 
In studying the effect of the storage of ice on the bacteria contained 
therein, Sparks (1908) concluded that ice, even when cut from water 
which may contain pathogenic bacteria, is utterly incapable of passing 
on the disease if it is stored for some time before using. Similar results 
were obtained by Reudiger, who found that Bacillus coli was destroyed 
by storing in ice for eight weeks, and that the Bacillus typhosus organism 
was dead at the end of thirty-one days. 
Budinoy (1909) inoculated sterile milk with Bacterium lactis acidi and 
noted the effect of temperature on the life of the organism. At 30° C. 
most of the bacteria were dead in nine days, and at room temperature 
very few were alive at the end of eighteen days; while at 0° C. there was 
no change after thirty days. Alternate thawing and freezing had little 
or no effect. In such a case, however, temperature acts indirectly. The 
more favorable the temperature for growth, the greater is the production 
of acid, which in turn destroys the bacteria. 
Poppe (1914) exposed the anthrax bacillus to a temperature of — 16° 
C. for two weeks. The virulence and the reproductive capacity of the 
organism were not affected. 
Jordan (1916) concluded that freezing had about the same effect as 
slow sand filtration, and that a great majority of the typhoid bacilli 
perish in a short time in ice, less than 1 per cent remaining alive after 
three weeks of freezing. 
Hilliard, Torossian, and Stone (1915) noted, in their work with Bacillus 
coli, that 99 per cent of the organisms were killed by freezing in tap water 
for three hours; in the case of Bacillus subtilis, 80 per cent were killed 
under similar conditions. When the bacteria were placed in cream con- 
taining 30 per cent of butterfat, a protective action was noted. 
