228 Transactions British Mycological Society. 



where very slight changes in morphology or biochemical pro- 

 perties have been acclaimed as the induction of a mutation. 

 These mutations may be merely the expression of a develop- 

 mental stage previously unrecognised ; new phases may present 

 new cultural reactions, and possess different biochemical 

 properties. If the presence of sub-cycles within the general 

 life-cycle be confirmed, such knowledge will go very far indeed 

 to explain many of the phenomena hitherto regarded as evidence 

 of mutation. Clearly until very much more is known of the 

 full life-histories of the organisms upon which the experimental 

 work is carried out it will, at least, be somewhat injudicious 

 to found upon the results of such experiments any very funda- 

 mental conclusions. 



Again a possible interfering factor which has received little 

 or no attention by the bacterial mutationists is that of the 

 genetic constitution of their organisms. In the higher animals 

 and plants the almost bewildering complications which con- 

 sideration of the gametic constitution of the individual 

 introduce into any experimental study, where absolute specific 

 purity is vital, render it imperative that the genetic relations 

 of the subject to be investigated be known with the most 

 scrupulous accuracy and in the minutest detail. If one is 

 examining the morphological and physiological behaviour 

 of a species of which such knowledge is totally lacking, 

 and drawing therefrom phylogenetic deductions, those deduc- 

 tions, and conclusions based upon them, will tend to be 

 unreliable. 



Now the lack of information concerning the genetic 

 behaviour of bacterial organisms is profound. Hitherto the 

 only recognised reproductive processes have been those of 

 binary fission and asexual spore formation. If analogies 

 drawn from the behaviour of higher plants have any value, 

 the recent investigations on somatic segregation may indicate 

 that the genetic processes involved even in binary fission may 

 have a significance greater than that with which they have 

 been accredited. If in addition there are further possible 

 avenues of segregation in such reproductive processes as 

 gonidial formation and gemmation, this matter may assume a 

 serious aspect. 



Furthermore it is not inconceivable that in the bacterial 

 life-cycle there may exist some phase more or less comparable 

 with the sexual fusions of other organisms. Lohnis and 

 Smith(22), for example, note a symplastic stage in which "the 

 living matter previously inclosed in the separate cells undergoes 

 a thorough mixing either by a complete disintegration of the 

 cell wall, as well as cell content, or by a ' melting together ' of 



