394 TIMOTHY UlCHARDS LEWIS. 



transparent, and then, apparently, disappearing more or less 

 completely ; and (2) by undergoing cleavage, and giving rise to 

 minute plastides. These may, occasionally, be observed'to pre- 

 sent a rosary-chain arrangement, but usually their identification 

 becomes impossible owing to their mixing with other molecules 

 in the field. 



I am not in a position to offer any suggestion as to which is 

 the normal course for bacilli to take, seeing that bacillus-filaments 

 may redevelop under suitable conditions from material derived 

 from preparations in which either of the two foregoing processes 

 has been observed to take place. Probably, to a greater or less 

 extent, both processes occur together ; at least it is seldom that 

 filaments will give rise to the bright, refractive molecules, in a 

 highly nutritious fluid, without a contemporaneous formation of 

 plastides taking place at some part of the preparation. 



G. — The relation of the Spirillum of Recurrent Fever to other 

 hioimi Spirilla. 



Having thus endeavoured to prove that no sufficient grounds 

 have been adduced for accepting the doctrine that bacilli have 

 been found in splenic disease, septicpemia, and so forth, which 

 differ, not only in any material respects, but in any respects 

 whatsoever, from bacilli which may be found under certain easily 

 induced conditions, it remains to be seen what evidence there 

 exists to show that the other member of the schizomycetes group 

 found in recurrent fever — SpiriUuni Obermeieri — differs from 

 other spirilla known to be harmless. 



On this point also considerable diversity of opinion exists, 

 though perhaps not quite to so marked an extent as with respect 

 to the microphytes which have just been considered. The matter 

 is, moreover, made somewhat simpler from the circumstance 

 that those who have had the greatest opportunities for personal 

 observation are, on the whole, the observers least inclined to claim 

 for this spirillum specific characters in the ordinary botanical 

 sense of the term. 



Since the period of its discovery in the blood by Obermeier it 

 has been referred to under various names : Spirothrix, Trotomy- 

 cetum recurreniis, in Lebert's article on recurrent fever and in 

 Ziemssen's ' Handbuch ' of Medicine ; Sjririllum by Erichsen, 

 Litten, Birch-Hirschfeld, &:c. ; Spirillum temte by Naunyn ; and 

 Sjnrochate Obermeieri by Cohn (fig. 15). 



The last-named observer, and the only one with an extended 

 botanical experience, gave it a specific distinction solely on 

 physiological grounds, as, after careful examination, he was unable 

 to detect any diference, either in size or in character of move- 



