THE WORLD OF INVISIBLE LIFE 
17 
touched on the first dish. If we do this three or 
four times, being very careful each time to have 
everything we use absolutely clean and free 
from any other microbes, we will have a large 
and pure growth of the microbe we wish to 
study. We can now take a portion of this 
growth, stain it, and look at it under the micro¬ 
scope. Thus we are able to study, in all its 
stages, the kind of microbe we have grown, and 
so learn all about its life and habits. 
How can 
microbes be 
studied? 
