108 ATLAS OF BACTERIOLOGY. 



Spores are much more resistant than vegetative 

 forms to all injurious influences. They require no 

 nourishment or water in order to remain capable of 

 germination for years and decades,* they are much 

 more indifferent to gases than bacilli, and the spores 

 of anaerobic varieties usually tolerate free oxygen 

 welLt 



The power of resistance of the spores to dry and 

 moist heat is very considerable. Dry heat is toler- 

 ated relatively very well, and many spores resist a 

 temperature of 100. In the moist condition a tem- 

 perature of 70 kills the anthrax bacillus in one 

 minute, while the spores resist this temperature for 

 hours, and in water or steam at 100 they live from two 

 to five minutes, occasionally even from seven to twelve 

 minutes. The varying resistance of different anthrax 

 spores (v. Esmarch: Z. H., V., p. 67) seems to be 

 partly a race peculiarity. It is very probable, more- 

 over, that the nutrient medium, the temperature at 

 the formation of the spores, the degree of maturity, 

 etc., also exert an influence upon the resistance. 

 Careful investigations on this subject are almost en- 

 tirely lacking, but Percy Frankland has shown that 

 spores formed at 20 are more resistant to light than 

 those formed at incubation temperature (C. B., XV., 

 p. 110). 



* According to an observation of v. Esmarch the virulence of 

 anthrax spores seems to be lost, in the course of time, before 

 their power of germination. 



f Dry garden earth containing the spores of malignant oedema 

 preserved the latter excellently in my laboratory for four y.ears. 

 On the other hand, tetanus spores which were dried on threads 

 and kept in the room had perished at the end of three days ; 

 they were still alive on the second day. 



