EFFECT OF TEMPERATURE UPON BACTERIA. 147 
45° to 55° C., and for the thermophilic species about 
75° C. There are no non-spore bearing bacteria which 
when moist are able to withstand a temperature of 
100° C. even for a few minutes. A long exposure to 
temperatures between 80° and 100° has the same result 
as a shorter one at the higher temperatures. Accord- 
ing to Sternberg, ten minutes’ exposure to moist heat 
will at 52° C. kill the cholera spirillum, at 54° C. kill 
the streptococcus, at 56° C. the typhoid bacillus, at 
60° C. the gonococcus, and at 62° C. the staphylococ- 
cus, the latter being about the most resistant of the 
pathogenic organisms which have no spores. 
When micro-organisms in a desiccated condition are 
exposed to the action of heated dry air the temperature 
required for their destruction is much above that re- 
quired when they are in a moist condition or when they 
are exposed to the action of hot water or steam. <A 
large number of pathogenic and non-pathogenic species 
are able to resist a temperature of over 100° C. dry 
heat for an hour. A temperature of 120° to 130° C, 
maintained for one and a half hours is required to de- 
stroy all bacteria, in the absence of spores, if dry heat 
is used. 
Spores are far more resistant to all injurious influ- 
ences than vegetative forms. They retain their power 
of germination for years without either nourishment or 
water, and are much more indifferent to the action of 
gases than bacilli, the spores of the anaérobic species 
being especially resistant to the action of oxygen. 
Spores possess a great power of resistance to both 
moist and dry heat. Dry heat is comparatively well 
borne, many spores resisting a temperature of over 
130° C. The spores of bacillus anthracis and of 
