408 c. cliffoi;d dobell. 



of variable form are seen in dried and stained preparations. 

 Their interpretation is not indicated. (This organism is 

 certainly worthy of a caT*efnl cytological study.) 



Federowitscli (1902) studied B. megatherium, B. pyo- 

 cj^aneus, and other Bacteria. He found stainable granules, 

 which play a part in spore-formation, in the cells. But he 

 believes that "no nucleus like that of higher cells" is 

 present. The method of fixation is not given; Weigert's- 

 stain was employed. 



Ruzicka (1908) finds granules present in many Bacteria 

 after fixation with HgClo and staining with methylene blue. 

 A definite interpretation is not given to the granules. In 

 later papers (Ruzicka, 1908, 1909, etc.) he advocates the 

 view that the bacterial cell represents a naked nucleus. 



Ficker (1903) discusses the problem of the nucleus in 

 Bacteria. He expresses the opinion that it is premature to 

 draw any conclusions with regard to either granules or nuclei. 



Mencl (1904), using careful cytological methods, finds 

 typical nuclei in Bacilli inhabiting the gut of the cockroach. 

 He also finds nuclei in B. megatherium. In 1905 h& 

 describes nuclei of many different forms in filamentous water 

 Bacteria (Cladothrix, etc.), after staining intra-vitam with 

 polychrome methylene blue. Later (Mencl, 1907) he gives a 

 minute description of Bact. gammari, describing the various 

 appearances seen in resting and mitotically dividing nuclei. 

 He also published in the same year (Mencl, 1907a) a more 

 detailed account of the symbiotic Bacteria of the cockroach. 

 Quite recently he has given a description of the nuclei in 

 Sarcina and Micrococci as revealed by staining with 

 polychrome methylene blue intra-vitam and subsequently 

 clearing in glycerine. Mend's results have been adversely 

 criticised by Guilliermond (1907, 1908, 1910) and Meyer 

 (1908). The latter states that MencFs nuclei are really volutin 

 granules; the former believes they are the septa formed in 

 the cells during cell-division. Mencl (1909) has replied to 

 Guilliermond's criticisms and maintains the correctness of his 

 own interpretations. 



