404 Mr. H. Wager. [Oct. 9, 



division stages remarkably like some of the stages in mitotic nuclear 

 division in the higher plants. In a later paper* Zacharias states that 

 although the central body contains nuclein it cannot be regarded as a 

 true nucleus. Biitschlij in the same year, on the other hand, comes 

 to a very definite conclusion that the central body is not only nuclear 

 in nature, but that it is the homologue of the nucleus of higher forms. 

 Fischer { controverted Biitschli's observations, and stated that the 

 appearances figured by that author are due to a plasmolyzed condition 

 of the cells. In a later paper he withdrew this statement, but he 

 still maintained that the central body is not of the nature of a 

 nucleus. Deinega|| was unable to come to any definite conclusion 

 as to the presence or absence of a nucleus. ZukalU considered certain 

 granules in the central body to be the nuclei. Hieronymus** 

 considered it to be an open nucleus, and to have a peculiar structure. 

 Pallaff says the central body is homogeneous, and contains no granules. 

 NadsonJ} says it is of a nuclear nature. Macallum finds that it 

 contains chromatin, but states that it is not a nucleus, and that there 

 is nothing resembling a nucleus in the Cyanophycese. Hegler|||| 

 comes definitely to the conclusion that, notwithstanding the absence 

 of a membrane and nucleolus, the central body is a nucleus, and 

 divides by a process of karyokinesis similar to that which occurs in 

 higher plants. Massart,lfU on the other hand, in 1901, basing his con- 

 clusions upon facts observed after staining the cell intra vitam with 

 methylene blue, states that not only does it not present the characters 

 of the nucleus of the higher plants, but that it cannot even be regarded 

 as a nucleus of a simpler type. 



It is obvious from these various contradictory statements that a. 

 considerable amount of caution is necessary in arriving at any con- 

 clusion as to the nature of the central body ; but I have very little 

 doubt from my own observations that it is of the nature of a nucleus, 

 that it possesses certain of the characteristics of the nuclei of the 

 higher plants, but not all, and that it can very fairly be regarded as a 

 nucleus of a simple or rudimentary type. 



* Bot. Zeit.,' 1890. 



t ' Ueber den Bau der Bacterieu, etc.,' Leipzig, 1890. 

 J ' Die plasmolyse der Baliterien/ 1891. 



' TJntersuchungen iiber den Bau der Cyanophyceen und Bacterien,' Jeuu, 

 1897. 



|| ' Bulletin Soc. Imper. des Nat.,' Moscow, 1891. 



f ' Sitzungsb. Kaiserl. Akad. in Wien,' 1892. 



** ' Cohn's Beitz. z. Biol. d. Pflanzen,' 1892. 



ft ' Jahrb. f . Wiss. Bot.,' 1893. 



Jt " Ueber den Bau des Cyanophyceen-protoplastes,' 1895. 



' Trans. Canadian Institute,' 1899. 



HII ' Jahrb. f. Wiss. Bot.,' 1901. 



TIT ' Sur le Protoplasme des Schizopliytes,' Brussels, 1901. 



