410 C. CLIFFORD DODELL. 



(1908), and Guilliennoud (1908). The various objections raised 

 against liis work have been answered by Swellengrebel 

 (1908, 1909), who maintains the correctness of his conclu- 

 sions. 



Guillierniond (1907) gives an excellent brief review of 

 previous results upon the cytology of Bacteria. In the follow- 

 ing year (Guilliermond, 1908) he describes the structure of a 

 number of Bacilli (B . radicos us, B. my coides, B. mega- 

 therium, etc.). He believes that in all these the nucleus 

 is in the form of granules of chromatin (chromidia) — distinct 

 from the metachromatic granules — scattered through the 

 cytoplasm. These granules become massed together to form 

 the spores. He criticises the results obtained by many other 

 investigators. Various cytological fixing and staining 

 methods were employed in his researches. In a more recent 

 paper, Guilliermond (1909) describes nuclei in the form of 

 spiral filaments — like those found by myself — in two species 

 of Bacillus (from the gut of Echinocardium) and a large 

 Spirillum. 



In 1908 I gave the results of cytological researches Avhich 

 I had undertaken upon the sti-ucture and life-history of 

 several Bacteria. I described a new large disporic Bacillus 

 — B. f lexilis, from the gut of frogs and toads — whose life- 

 history is essentially the same as that of B. biitschlii 

 described by Schaudinn (1902). I also described another 

 organism — which I named Bacillus spirogyra — from the 

 same hosts, in which the nucleus is in the form of a spiral or 

 zig-zag filament. I described further in Spirillum mono- 

 spora — fi'om the frog and toad also — a nucleus of the 

 chromidial form. The chromidia mass themselves together 

 in forming the spores. In 1909 I gave a more detailed 

 description of B. spirogyra. I discussed the nature of the 

 nuclear filament, and described the ptirt it played in spore- 

 formation — a process which I described in detail. I descibed 

 in addition the structure and method of spore-formation in 

 B. lunula, which resembles in these respects B. spirogyra, 

 As a result of this work, I reached the conclusion that the 



