504 The Modes of Division of Spirochseta recurrentis, etc. 



The Spirochetes exhibit characteristics of both Protozoa and Bacteria. The 

 reasons for considering them as Protozoa have been well set forth by 

 jSTuttall (1908), while Swellengrebel (1907) considers them to be Bacteria, 

 belonging to the family Spirillacece. On the whole, we consider that the 

 protozoal characteristics of Spirochetes preponderate over their bacterial 

 characteristics. 



We have much pleasure in thanking Prof. Nuttall for the material used in 

 these researches. 



Summary. 



1. The observations recorded in this paper were made on living 

 Spirochetes. AVe have previously examined much fixed and stained 

 material. It is very necessary to examine living material, as results based 

 only on stained preparations are not always reliable. 



2. Both longitudinal and transverse division occur in Spirochetes as seen 

 in S. recurrentis, S. duttoni, S. anoclontce, and & balbianii. 



3. Longitudinal division of S. recurrentis and S. duttoni is best seen when 

 there are but few Spirochetes in the blood. This is the case at the onset of 

 infection and at its close. In longitudinal division, rapid waves pass down 

 the body of the Spirochete. At one end a split occurs, which gradually 

 widens. Waves travel down each of the diverging daughter forms, which 

 ultimately lie at an angle of 180° with one another. The daughter 

 Spirochetes then separate. Organisms about to divide longitudinally are 

 slightly stouter than the others. 



4. Transverse division of S. recurrentis and S. duttoni also occurs. It is 

 initiated by the appearance of waves passing from both ends towards the 

 centre of the organism (which centre acts as a node). These waves meet and 

 die out, and return waves pass rapidly from the centre towards each end. 

 These processes are repeated many times, the frequency of the waves 

 increasing and the nodal region becoming thinner. Finally, after a succession 

 of very rapid waves, division occurs at the node and two complete daughter 

 organisms result. 



5. There is a periodicity in the direction of the division of S. recurrentis 

 and S. duttoni. At the onset of infection, longitudinal division occurs. This 

 is followed by transverse division of the Spirochetes when the infection is at 

 its height, while, with the diminution in numbers of the parasite as the 

 infection draws to an end, there is a reappearance of longitudinal division. 

 Naturally, there are times when both forms of division occur together. Our 

 observations relating to periodicity were made on peripheral blood of the 

 host. 



