BACTERIA 



stances, when certain agencies or conditions, such as absence of 

 food, drying, and heat, threaten the extinguishment of the organ- 

 ism. Spores are bright, shining, oval, or round bodies, which do 



PIG. 9. The formation of 

 spores. (After Fischer from 

 Frost and McCampbell.) 



FIG. 10. Spores and their location in bac- 

 terial cells. (After Frost and McCampbell.) 



not take aniline dyes readily, and which, when they are stained, 

 retain the color more tenaciously than the adult cells. They 

 resist heat, often withstanding a temperature of i5oC. dry heat 

 for an hour. Steam under pressure at a temperature of i5oC. 

 will invariably kill them after a short exposure. 



fl 8 



FIG. ii. Spore germination, a, direct conversion of a spore into a bacillus 

 without the shedding of a spore-wall (B. leptosporus) ; b, polar germination of 

 Bad. anthracis; c, equatorial germination of B. suUilis; d, same of B. mega- 

 terium; e, same with "horse-shoe" presentation. (After Novy.) 



Spores are situated either in the ends of the adult organism 

 (polar) or in the middle (equatorial), and the spore is discharged 

 (sporulation) either from the end or through the side. 



