52 FORMATION AND GERMINATION OF SPORES. 



sistant than the vegetative forms. They require no 

 nourishment and no water in order to retain their ability 

 to germinate after years and often decades. l They are 

 more indifferent to gases than the bacilli, the spores 

 of anaerobic varieties usually bearing free oxygen well. 2 

 Spores are obtained by carefully removing sporulating agar 

 streak cultures, and warming the emulsion, prepared with 

 a little water, to 70 for five minutes. 



Very important is the resistance of spores to dry and 

 moist heat. Dry heat is especially well borne, a tempera- 

 ture of 100 being withstood by many spores for a long 

 time. In a moist condition, a temperature of 70 kills the 

 anthrax bacillus in one minute; on the contrary, anthrax 

 spores withstand this temperature for hours; even in boil- 

 ing water or live steam at 100 they die only after two to 

 five, or at times after seven to twelve, minutes. The vary- 

 ing resistance of different anthrax spores (v. Esmarch, 

 Z. H. v, p. 67; Stephanidis, A. H. xxxv, 1) appears to be 

 partly a race peculiarity, but very probably also the 

 nutrient medium, the temperature at which they were 

 produced, the degree of maturity, etc., exert an influence 

 upon the resistance. Very accurate investigations upon 

 these points are almost entirely lacking. We only know 

 from Percy Frankland that spores formed at 20 are more 

 resistant to light than those originating at incubator tem- 

 perature (C. B. xv, p. 101). 



The resistance of spores is tested by hanging in the 

 boiling steam-chamber little sacks of tulle containing frag- 

 ments or little plates of glass upon which anthrax spores 

 have been dried, and from minute to minute a sack is re- 

 moved and the pieces of glass laid upon an agar plate, 

 which is then kept at incubator temperature. A better way 

 it seems to me is as follows: Ic.c. of an emulsion of spores 

 is placed in 20 c.c. of water, and after shaking well five 



1 According to an observation of v. Esmarch, if anthrax spores are 

 kept a long time the virulence appears to be reduced before the power 

 to vegetate is affected. 



2 Spores of malignant edema in garden earth were well preserved in 

 my institute for four years. On the contrary, very astonishingly, 

 tetanus spores dried upon threads and kept in the room were still alive 

 after two days, but dead after three days. 



