FORMATION AND GERMINATION OF SPORES. 129 



form spores. This may take place on the next day, 

 but the time varies very much according to the 

 amount of material inoculated, to the size of the drop, 

 and to the temperature to which they are subjected. 

 The process may be watched for about two hours, a 

 high power of the miscroscope being used with a dry 

 lens. At first a bright spot,' hardly to be distinguished 

 from the rest of the protoplasm, which is homogeneous 

 or finely granular, makes its appearance in some of the 

 cells. Gradually it grows brighter and larger, until, 

 finally, it appears as a strongly refracting body with 

 sharp outlines about as large as the future spore. It 

 now stands out clearly from the encircling mother- 

 bacillus, which by degrees seems to fade away, until 

 at last it disappears altogether. Then the spore alone 

 remains; by this time it can be seen to be surrounded 

 with a strong membrane. 



If a few of these spores are introduced with a 

 sterilized platinum wire into a fresh drop of sterilised 

 bouillon which is placed in the moist chamber, after a 

 few hours germination begins. The exact time which, 

 must be allowed cannot be stated, as the rapidity 

 with which development takes place depends upon dif- 

 ferent circumstances, especially upon the temperature 

 In order, to watch this development conveniently, it is 

 best to place the slides which act as moist-chambers 

 on glass benches in the incubatoi*, which is kept at a 

 temperature of from 22° to 24° C. The most con- 



K 



