BACTERIA AS PLANTS. 



conditions. The same may happen among the 



spherical forms, which only in rare instances form 



endogenous spores. 



Among the spheres 



which form a chain 



of streptococci some 



may occasionally be 



slightly different 



from the rest. They 



are a little larger, 



and have been 



thought to have an 



increased resisting 



power like that of 



true spores (Fig. 13 FIG. 13. So - called arthrogenous 



&}. It is quite doubt- spores: a, Forming as segments 



f ul, however, wheth- f f ^ b ' As segments of a chain 

 er it is proper to re- 

 gard these bodies as spores. There is no good 

 evidence that they have any special resisting 

 power to heat like endogenous spores, and bac- 

 teriologists in general are inclined to regard them 

 simply as resting cells. The term arthrospores 

 has been given to them to indicate that they are 

 formed as joints or segments, and this term may 

 be a convenient one to retain although the bodies 

 in question are not true spores. 



Still a different method of spore formation 

 occurs in a few peculiar bacteria. In this case 

 (Fig. 14) the protoplasm in the large thread breaks 

 into many minute spherical bodies, which finally 

 find exit. The spores thus formed may not be all 

 alike, differences in size being noticed. This 

 method of spore formation occurs only in a few 

 special forms of bacteria. 



The matter of spore formation serves as one 



