GENERAL MORPHOLOGY AND PHYSIOLOGY. 



considerably wider, but is never longer than the 

 parent cell. 



Arthro-spore formation is illustrated in Leuco- 

 nostoc mesenteroides. Certain elements in the chain 

 of cocci, apparently not differing from the rest, 



FIG. 54. A THREAD OF BACILLUS ANTHRACIS WITH SPORES, IN A 

 DROP-CULTIVATION, x 1400. 



become larger, with tougher walls, and more refrac- 

 tive (Fig. 55). The remaining cells die, and these 

 cells having acquired the properties of spores are 

 set free, and can reproduce a new growth in any 



FIG. 55. I EUCONOSTOC MESENTEROIDES ; COCCI-CHAINS WITH 

 ARTHROSPORES (after Van Tieghem and Cienkowski). 



fresh nourishing soil. That this occurs in all species 

 which do not form endospores is at present only 

 a supposition. 



Spores are invested by a thick membrane, which 

 is believed to consist of two layers. To this they 

 probably owe the property they possess of retaining 

 vitality when desiccated, and of offering a greater 



