4 MORPHOLOGIC VARIATION 



reserve material and protected by a more or less resistant membrane. Go- 

 nidia and regenerative bodies participate actively in the process of multiplica- 

 tion, whereas the other reproductive organs are in the first place resting forms. 

 Gonidia, regenerative bodies, and probably microcysts are produced by all 

 bacteria, while arthrospores, exo- and endospores are less common; though 

 there are indications that they will be discovered in many more cases, as soon as 

 these problems are more thoroughly investigated (1921, p. 162). 



All bacteria live, in vivo as well as in vitro, alternately in an organized 

 and in an amorphous stage. By the partial or complete dissolution of the 

 vegetative and reproductive cells, a plasmatic mass, the symplasm, is formed, 

 which, after a period of rest, according to circumstances may transform itself into 



new cells of the same or of a more or less modified character The 



formation of the bacterial symplasm proceeds always in two phases: First, the 

 cells agglomerate to smaller or larger clumps; second, a more or less complete 



dissolution of the cells takes place, resulting in a crumbly or slimy mass 



The reconstruction of new cells from the bacterial symplasm follows various 

 lines according to the internal as well as the external conditions (quality of 

 the symplasm, environment, and technique). At first always regenerative 

 units become visible, which either grow up separately to new cells, or of which 

 several may agglomerate and surround themselves with a uniting membrane, 

 thus forming at once full-grown cells. (1921, p. 195). 



He also describes another process as conjunction, where two or 

 more cells combine without previous disintegration. Lohnis is care- 

 ful to point out that "by discussing the life cycles of bacteria we do 

 not intend to revive any of those unclear theories concerning bac- 

 terial polymorphism or pleomorphism. The development of bacteria 

 is characterized not by the irregular occurrence of more or less abnor- 

 mal forms but by the regular occurrence of many different forms and 

 stages of growth connected with each other by constant relations" 

 (1916, p. 677). But the diagram which he presents to show these 

 constant relations, with its numerous arrows connecting each type 

 with many others, and with double points indicating their reversi- 

 bility, leaves one without any clear notion of regularity, but rather 

 with the idea, in vogue in Naegeli's day, that any bacterial type 

 may develop in a hap-hazard way from any other. Indeed, from 

 neither text nor illustrations can one gain any exact impression of 

 the sequence of events in the life cycle he postulates. 



Mellon, in a long series of papers extending over ten years, has 

 described morphologic variations in diphtheroid bacteria, typhoid and 

 colon bacilli, and fusiform organisms; many of his papers deal with 



