juiy 31, 1916 Life Cycles of the Bacteria 697 



Globular forms of different size sometimes showing a 



thin protruding rodlike form, irregular curved or 



clublike forms which later produce normal rods Our type I 



Budding large globules, budding and branching rods 



and threads Our type K 



Large rods and threads Our type L 



Pointed rods containing large granules Our type M 



This complete agreement is indeed very interesting, and as we our- 

 selves have not worked with any representative of this group of organ- 

 isms, De Negri's observations furnish a very welcome extension and con- 

 firmation of our statements concerning the life cycles of all bacteria. 

 De Negri himself unfortunately failed to see that he was touching this 

 general problem. He confined his studies almost exclusively to those 

 corynebacteria causing "malignous granulom" and to some closely 

 related forms. Therefore he was carried away to the entirely incorrect 

 conclusion that those large budding forms were some kind of ' ' blastomy- 

 cetes," and the organism studied by him should be separated from the 

 bacteria and placed among the Fungi Imperfecti. A comparative study 

 of any of the common bacteria — for example, B. subtil is — would easily 

 have prevented this serious error. 



For diagnostic and systematic purposes a full knowledge of the life 

 cycles of the bacteria will naturally be of the greatest importance. In 

 our opinion the following morphological details should be studied in 

 every case. 



1. Vegetative cells; formation and germination of spores 



Spore-free and spore-bearing cells 

 Arthrospores, formation and germination 

 Endospores, formation and germination 

 Exospores, formation and germination 



2. Conjunction of different cell types 



3. Gonidia, formation and development 



Budding, liberating, germination, development in toto to regenerative 

 bodies, to exospores, or to full-sized cells 



4. Symplasm, formation by 



Spore-free cells 

 Spore-bearing cells 

 Arthrosporest 

 Endospores and exospores 

 Regenerative bodies 

 Gonidia 



5. Regenerative bodies 



Formation by 



Spore-free and by spore-bearing cells 



Arthrospores, endospores, and exospores 



Gonidia of different types 



Symplasm of different origin 

 Germination of the different types 

 Development in toto to vegetative cells or to spores 



