10 



III. 



LIFE HISTORY OF A BACTERIAL CELL. 



Young cells grow, attain full size, multiply. 

 Spore formation, analogy of spores to seeds of higher 

 plants. 



Observed in many bacilli, few spirals, but not in 



micrococci. 



Sporogenic granules their coalescence the spore. 

 Spore germination observed in but few instances. 



Bacillus snbtilis, Cohn ; Bacillus butyricus, Praz- 



movski. 

 Bacillus anthraci?, Koch ; Bacillus megaterium, 



DeBary. 



Each spore gives rise to but one bacterial cell, and a 

 cell develops but one spore. Spore formation, therefore, 

 a means of reproduction, not of multiplication. 



Structure of a spore dense, highly resistant cell- wall 

 the contents. 



Behavior of aniline dyes. Action of heat, cold, 



desiccation, chemicals. 



Their importance as resting or permanent forms. 

 Position of the spore in the cell median or termi- 

 nal with or without enlargment. Clostridium form 

 Drumstick or u Kopchen v form. 



Attempts at classification Endospore and arthro- 

 spore bacteria. 



Spore formation not the result of exhaustion of soil, 

 but like the flower and fruit of plants represents the high- 

 est stage of development. It occurs only under favorable 

 conditions medium, temperature, oxygen. 



Asporogenic bacteria, result of unfavorable environ- 

 ment influence of calcium. 



