352 



Dr. D. Ellis. 



[May 17, 



and developed into typical Cladothrix threads : probably both sequences 

 followed. Winogradsky, writing on this point, says : " Nur dann konnte man 

 den genetischen Zusammenhang eines Spirillum mit Cladothrix fur bewiesen 

 halten, wenn er einen Cladothrix-faden aus einem echten noch gewissermassen 

 unter Beibehaltung seiner characteristischen Eigenschaften sich teilenden 

 Spirillum erzogen hatte." It is proved at any rate that spiral forms with 

 spiral movements and polar cilia are liberated from what was undoubtedly 

 a Cladothrix colony. These appear in the surrounding water as organisms in 

 no respect different from what are commonly regarded as Spirilla. Their 

 subsequent fate is immaterial to the point at issue, so long as it is proved 

 that they originated from a Cladothrix thread. One cannot doubt that 

 sooner or later they settle down and develop into the typical threads. This 

 point has not been proved. If this proof were furnished it would be an 

 interesting addition to our knowledge of this organism, but would have only 

 a slight bearing on the point under discussion : the essential point lies in the 

 proof of the existence of Spirilla originating from a Cladothrix thread, not 

 in proving what becomes of them after they have been formed. 



The Formation of Cocci. — According to Zopf, Cladothrix also multiplies by 

 a splitting up of its cells into cocci. I have not observed this method of 

 multiplication. It is common in the case of Crenothrix polyspora when 

 growing under unusually favourable circumstances (see Garrett, ' Public 

 Health,' No. 1, 1896), and one must bear in mind that when during active 

 growth the elongation of bacterial cells does not keep pace with their 

 division, the length of the cells in such a culture is not greater than their 

 breadth, and consequently cocci-like rods are formed. It is possible that 

 Zopf may have observed such a phenomenon. As young Crenothrix threads 

 resemble Cladothrix threads, it is also possible that he may have mistaken 

 the former for the latter. The matter must be regarded as not yet settled. 



Synopsis of Methods of Reproduction. — We may, therefore, enumerate 

 the following kinds of reproductive organs as occurring in Cladothrix 

 dichotoma : — 



a. Kod-shaped swarm cells, 

 o. Spirally shaped swarm cells. 



c. Kod-shaped swarm f ragments. 



d. Spirally shaped swarm f ragments. 



e. Kod-shaped non-motile fragments. 



Artificial Cultures. — Biisgen was the first to obtain artificial cultures. He 

 was followed ' by Hoeflich (12), who gave a very complete and accurate 

 account of the growths of this organism in various media. My own 



