GENERAL CHARACIVERISTICS OF BACTERIA. 49 
the interior of a cell very much enlarged in its central 
portion, giving it a spindle shape. 
The germination of spores takes place as follows : 
By the absorption of water they become swollen and 
pale in color, losing their shining, refractile appear- 
ance. Later a little protuberance is seen upon one side 
or at one extremity of the spore, and this rapidly 
grows out to form a rod which consists of soft-growing 
protoplasm enveloped in a membrane which is formed 
of the endosporium or inner layer of the cellular en- 
velope of the spore The outer envelope, or exosporium, 
is cast off, and may be seen in the vicinity of the 
newly-formed rod. Sometimes the vegetative cell 
emerges from one extremity of the oval spore, and 
in other species the exosporium is ruptured and the 
bacillus emerges from the side. 
In old cultures of bacteria, where the deleterious sub- 
stances have developed and the food-stuffs have been 
largely used, there are frequently found very irregular 
or distorted forms, due to the abnormal development and 
division of the bacterial cells under the unfavorable 
conditions present. These are spoken of as involution 
or degenerated forms. If these deformed cells are placed 
under suitable conditions they produce again normally 
fashioned organisms. 
