34 PATHOGENIC BACTERIA. 



want of food and because of the presence of other con- 

 ditions unfavorable to their existence." 



When the conditions for rapid multiplication are no 

 longer good, the organism assumes a protective attitude 

 and develops in its interior small oval eggs, seeds, or, as 

 they are more correctly called, spores (Fig. i). Such 



a b c d e f 



.CJED c: g) o o o 



FIG. I. Diagram illustrating sporulation : a, bacillus enclosing a small oval 

 spore ; b, drumstick bacillus, with the spore at the end ; c, clostridium ; d, free 

 spores ; e and f y bacilli escaping from spores. 



spores developed within the bacteria are called endospores. 

 When the formation of such a spore is about to com- 

 mence, a small bright point appears in the protoplasm, 

 and increases in size until its diameter is nearly or quite 

 as great as that of the bacterium. As it nears perfection 

 a dark, highly-refracting capsule is formed about it. As 

 soon as the spore arrives at perfection the bacterium 

 seems to die, as if its vitality were exhausted in the 

 development of the permanent form. 



Endospores are generally formed in the elongate bac- 

 teria bacillus and spirillum but Zopf has described 

 similar bodies as occurring in micrococci. Escherich 

 also claims to have found undoubted spores in a form 

 of sarcina. 



The spores found in the bacilli are either round or 

 oval. As a rule, each bacillus produces a single spore, 

 which is situated either at its centre or at its end. When, 

 as sometimes happens, the diameter of the spore is greater 

 than the diameter of the bacillus, it causes a bulging of 

 the organism, with a peculiar appearance described as 

 clostridium. When the distending spore is in the centre 

 of the bacillus, it produces a barrel-shaped organism; 

 when situated at the end, a u Trommelschlager, " or drum- 

 stick-shaped one. As the degeneration of the protoplasm 

 of the bacillus sets the spore free, it appears as a clear, 



