MORPHOLOGY, REPRODUCTION, ETC. 



17 



8 4 n? 



Fig. 4. — Various Positions of Spokes 

 IN Bacterial Cell. 



membrane which is very resistant. Muhlschlegel ' believes that the spore 

 membrane is a double structure, and, as stated before, Nakanishi believes 

 that the spore contains nuclear material. 



The position of the spore in the mother cell is of some differential 

 importance in that it is usually con- 

 stant for one and the same species. 

 Thus, the spores of the tetanus 

 bacillus are regularly situated at 

 the extreme ends of the bacillary 

 bodies, while those of anthrax are 

 situated at or near the middle. 



Physiologically, sporulation is probably to be regarded as a method 

 of encystment for the purpose of resisting unfavorable environment, 

 ^ and it is indeed true that species 



of bacteria the vegetative fonns of 

 which are rather easily injured by 

 heat, light, drying, and chemicals 

 have a comparatively enormous re- 

 sistance to these agents after the 

 formation of spores. Thus, while a 

 10-per-cent solution of carbolic acid 

 will kill the vegetative forms of 

 anthrax bacilli within twenty min- 

 utes, anthrax spores are able to resist 

 the same disinfectant for a long 

 period in a concentration of over 50 

 per cent; and while the vegetative 

 forms of the same bacillus show little 

 more resistance against moist heat 

 than other vegetative forms, the 

 spores will withstand the action of 

 live steam for as long as ten to twelve 

 minutes and more. 



Whenever the spores of any mi- 

 croorganism are brought into an en- 

 vironment suitable for bacterial growth as to temperature, moisture, 

 and nutrition, the spores develop into vegetative forms. This process 

 differs according to species. In general it consists of an elongation of 



al e i * f 3 ^ 



0000<?cPon 



ale J- 



oOO C^ 



A^f 



B 



*0 



jLiJ 



aO iO "W ^ 



Fig. 5. — Germination op Spokes. 

 A, Bacillus subtilis, equatorial spore 

 germination; B, Bacillus anthracis, 

 germination by simple transition; C, 

 Clostrydium butyricum, polar germi- 

 nation. 



I MiMschlegel, Cent. f. Bakt., 11 Abt., vi, 1900, p. 65. 



