FORMATION AND GERMINATION" OF SPORES. 107 



pulmonum and the peculiar spirillum endoparagoci- 

 cum. 



As H. Buclmer (C. B., YIII., 1) showed, the for- 

 mation of spores takes place in suitable varieties 

 when the nutrient medium is beginning to be ex- 

 hausted, i.e., it is most rapid in very poor media. 



On the other hand, a good nutrient medium not 

 alone facilitates the development of the bacilli but 

 also that of the spores, in so far as the vigorously 

 growing bacilli also sporulate luxuriantly and con- 

 stantly. The crop of spores is disproportionately 

 large. Whether the quality (power of resistance) of 

 the spores, which grow upon different nutrient media, 

 also differs, does not seem to have been investigated 

 methodically. 



The temperature must sometimes (always ?) be 

 higher for sporulation than for vegetative growth. 

 For example, the bacillus anthracis flourishes at 

 13-14, but does not form spores under 18. 



All aerobic bacteria require the entrance of oxygen 

 particularly for sporulation. The mode in which 

 facultative anaerobic varieties act has not been as- 

 certained. 



Strict anaerobics produce spores only on the exclu- 

 sion of oxygen or on the admission of oxygen in 

 mixed cultures or when synergetic bacteria have 

 perished. 



Spores never germinate in the exhausted nutrient 

 medium in which they have been formed, or which 

 has been affected injuriously by the products of dis- 

 assimilation. It is only after removal to a new nu- 

 trient medium that germination takes place (the mor- 

 phological details have been described on page 79) . 



