MORPHOLOGY AND RELATIONSHIPS OF MICROORGANISMS 37 



Arthrospores are bacterial cells set apart for purposes of repro- 

 duction, and are usually differentiated appreciably from the normal 

 cell. Several investigators have claimed that they are produced 

 by some of the cocci, but this has never been satisfactorily estab- 



B 00 Q fl 



y 



coo 



Fig. 16. Germination of spores: A, Bacillus subtilis (Prazmowski) ; B, Bacil- 

 lus anthracis (deBary) ; C, Clostridium sp. (deBary) . 



lished. The filamentous bacteria or trichobacteria produce 

 arthrospores or conidia, as they are sometimes called, by the dis- 

 integration of some of the filaments into short rods or spheres 

 which are capable of reproducing the parent type or by a process 



A i BC/ V) C 



Fig. 17. Arthrospores: A, Crenothrix polyspora (Cohn); B, GallioneHa ferru- 

 ginea, showing conidia formation (Ellis) ; C, Leptothrix ochracea (Ellis) . 



of budding. In many cases the threads which break up into 

 the spores are somewhat differentiated from the normal cells of 

 the plant, and are aerial, resembling closely some of the molds. 



MORPHOLOGY OF THE YEASTS, SACCHAROMYCETES, AND BLASTO- 



MYCETES 



Yeasts, from the standpoint of the systematic botanist, are 

 placed at some distance from the bacteria, for there are many 

 differences between typical yeasts and typical bacteria. On the 

 other hand, there are forms which intergrade between the two, 



