74 MICRO-ORGANISMS AND DISEASE. [CH. ix. 



the spores of bacilli will be thereby killed, and thus the fluid 

 becomes free of all other organisms except the spores. 



When spores are sown in a nourishing material, fluid or 

 solid, and when this is exposed to a temperature of about 32 

 to 38 C., the spores after the lapse of a few hours, in some 

 cases six (spores of anthrax -bacillus), in others two to four 

 hours (spores of hay-bacillus), in others more than six hours, 

 are seen to germinate, each spore growing into a bacillus. In 

 the case of solid nourishing material the presence of moisture 

 is essential. 



In this germination what one sees is this : the spore increases 

 in thickness, it then loses its dark contour at one pole or at 

 one of the long sides, and at this point a pale projection 

 appears. This projection increases in length and gradually 

 becomes as long as a bacillus, the investment of the spore 

 gradually fading away. This new bacillus soon divides into 

 two, and so on. 



The spores are capable of germinating independently of the 

 free access of air. 



