CHAPTER VI 



Sexuality in Bacteria 



A: THE EXISTENCE OF SEXUALITY 



THE process of sexual fusion is a normal part of the nuclear cycle of 

 most of the cytologically distinct types o£ bacteria which have been 

 described in the foregoing pages. The mechanism is very similar in 

 each case, and differs in no essential particular from similar processes in 

 algae, fungi and protozoa. A variety of exceptional methods of sexual re- 

 production have also been described, but even these are more remarkable 

 for their orthodoxy than for any characteristics which may be considered 

 pecuHar to bacteria. This is not a suitable place to discuss the problem of 

 whether bacteria are or are not a homogeneous group, but it is true that, 

 whereas they may be of widely divergent philogeny, the recorded differences 

 in their sexual mechanisms are no greater than may be found in any other, 

 comparable group. 



Although the outlines of the sexual cycle, as they appear from cytological 

 studies, are exceedingly well confirmed by such genetical evidence as is 

 available, the entire process of fusion and reduction is not known in every 

 case. The most notable omission is a convincing account of reduction as it 

 occurs in non-sporing eubacteria, in which two distinct types of nuclear 

 fusion have been described, one in the vegetative and one in the resting 

 condition. 



B: SEXUALITY IN SPORING BACILLI 



(i, 3, 8, 10, 12, 15, 26, 28, 29) 



Vegetative sporing bacilli may be of either rough or smooth morphology. 

 The larger species are almost invariably rough and contain a typical arrange- 

 ♦ ment of four cells in the bacillus (Chapter III). The multicellular nature of 



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