On the Morpliology and Physiology of the Cell. 205 



let us consider what steps have been taken towards the 

 sohition of the numerous cognate inquiries. 



1. Is a nucleus universally present ? The group Monera 

 was erected by Hseckel * in 18G8 for the reception of 

 the numerous very simple protoplasmic organisms in which 

 no nucleus had been detected, and in wliich he assumed 

 none to exist. The discovery of a distinct nucleus in 

 Foraminifera by F. E. Schultzef and Eichard HertwigJ 

 cast serious doubts upon the distinctness of the group, so 

 that Glaus § and others have proposed its entire abandon- 

 ment. Among plants, too, a vast number of the lower alg^e 

 and fungi, formerly considered destitute of nuclei, have been 

 shown always to possess one or even many, so that Schmitz 

 holds that Thallophytes destitute of a nucleus are altogether 

 unlvQOwn. II The Bacteria, however, still remain, and although 

 a re-examination of such forms as Protomyxa is very desirable, 

 it seems more probable that there really exist certain low 

 forms in which the protoplasm may be non- nucleated. 



2. Passing over the numerous investigations as to the 

 internal structure of the nucleus, it may be noted that JMac- 

 farlane IT has recently draAvn attention to a minute spheroidal 

 body commonly present within the nucleolus, which, though 

 occasionally figured, has never been thought of any im- 

 portance. He terms this the endo-nucleolus ; and in later 

 papers he points out the great constancy of its occurrence in 

 both animal and vegetable cells, and asserts that the division 

 of the cell starts from this innermost body, which divides 

 before the nucleolus and this before the nucleus. 



3. Great attention has recently been paid to multinu- 

 cleate cells. Schmitz** fovmd numerous nuclei in Siphono- 

 cladaceae, etc. Maupasff counts as many as from 150 to 



* Monographie Moueren. Jena Zeitschr,, iv., 1868, 

 + Rliizopoden Studieii. Archiv. f. Mikrosk. Anat., i. 



X Benierk. z. Organ, u. systemat. Stellung d. Forani. Jena Zeitschr,, x,, 

 1876. 

 § Lehrbuch d. Zoologie, 4te Auflage, "Wien, 1880. 

 li Journ. Ro}-. Micro. Sci., 1880, p. 482. 

 H Trans. Bot. Soc. Edin., 1880. 

 ** 02). cit. 

 ft Journ. Roy. Micro. Sci,, 1880, p. 106. 



