STUDY OF SPORE-FORMATION. ifij 



ined microscopically, and the condition of the organ- 

 isms noted. It is then to be retained in a warm 

 chamber especially devised for the purpose and kept 

 under continuous observation. The form of chamber 

 best adapted for the purpose is one which envelops the 

 whole microscope. It is provided with a window 

 through which the light enters, and an arrangement for 

 moving the slide about from the outside. The forma- 

 tion of spores requires a much longer time than the 

 germination of spores into bacilli, but with patiencie 

 both processes may be satisfactorily observed. 



It will be noticed that the description of this process 

 is very much like that which has just been given, but 

 differs from it in one respect, viz., that in this manip- 

 ulation we are not making a preparation which is simply 

 to be examined and then thrown aside, but it is an actual 

 pure culture, and must be kept as such, otherwise the 

 observation will be worthless. For this reason the 

 greatest care must be observed in the sterilization of all 

 objects employed. Studies upon spore-formation by this 

 method frequently continue over hours, and sometimes 

 days, and contamination must, therefore, be carefully 

 guarded against. The study should be begun with the 

 vegetative form of the organisms ; the hanging-drop 

 preparation should, for this reason, always be made 

 from a perfectly fresh culture of the organism under 

 consideration, before time has elapsed for spores to 

 form. 



The simple detection of the presence or .absence of 

 spore-formation can in many cases be made by other 

 methods. For example, many species of bacteria which 

 possess this property form spores most readily upon 

 media from which it is somewhat difficult for them to 



