500 



The Modes of Division of Spirochseta recurrentis and S. duttoni 

 as observed in the Living Organisms. 



By H. B. Fantham, D.Sc. Loud., Christ's College, Cambridge, Assistant to 

 the Quick Professor of Biology in the University, and Annie Porter, 

 B.Sc. Loud., University College, London. 



(Communicated by Prof. G. H. F. Nuttall, F.RS. Eeceived July 26, 1909.) 



(From the Quick Laboratory, Cambridge.) 



The exact mode of division of Spirochetes is still a matter of controversy. 

 Some workers, as Prowazek, and most of the German school of protozoologists, 

 consider that Spirochetes divide longitudinally, while Novy, SwellengrebeL 

 Laveran and Mesnil, and most French workers consider that they divide 

 transversely. Unfortunately, the direction of division of Spirochetes has 

 been made a criterion of their protozoal or bacterial nature. Too much stress 

 appears, from this point of view, to have been laid on the mode of division in 

 Spirochetes. Fantham (June, 1907, and January, 1908), in the case of 

 Spirocha'ta balbianii and S. anodontce, and Dutton and Todd (November, 

 1907), in the case of S. duttoni, state that both longitudinal and transverse 

 divisions occur, while Breinl (November, 1907) figured (but did not describe 

 in detail) both modes of division in S. duttoni. Fantham worked on both 

 living and stained material. Miss Mackinnon (1909), working in the Quick 

 Laboratory, has recently shown that both modes of division occur in 

 S. recurrentis. We hope to show in this paper, from observations on the 

 living organisms, that both methods of division certainly do occur in 

 Spirochetes ; also how these processes are brought about, and to put forward 

 suggestions explaining the phenomena. 



The subject is one of great difficulty, and the intrinsic difficulty has 

 not been lightened by the methods adopted by various investigators. Too 

 much reliance has been placed on the examination of fixed and stained 

 preparations of Spirochetes, to the exclusion of evidence which might have 

 been derived from observation of the living organisms. It is only recently 

 that the importance of observations of living material in protistology has been 

 recognised, and even now it is not sufficiently appreciated. 



During the past year we have observed living S. recurrentis and S. duttoni 

 at various times. The investigations were conducted at first independently 

 (those on S. duttoni by A. P., and those on S. recurrentis by H. B. F.) ; 

 afterwards we worked in collaboration and carefully checked and correlated 



