GENERAL CHARACTERISTICS OF BACTERIA. 47 
characters, therefore, of the various organisms whenever 
spores are mentioned, it will be understood that only 
the endogenous spores are meant. 
Unstained spores in slightly distended bacilli. (The spores are the light 
spots in heavily stained bacilli.) 
Fig. 12. 
Spores in distended ends ot Unstained spores in centre of bacilli 
bacilli. arranged in chains.. 
The production of endospores in the different species 
of bacteria, though not identical, is very similar. To 
observe the formation of spores in any species it is best 
to employ a streak culture on nutrient agar or a potato 
culture, which should be kept at the temperature nearest 
