Structure and Division of the Vegetable Cell. 193 



ill turn eventually split up ; and between them the cellulose 

 wall is formed. He does not attach any special significance 

 to the nucleolus. This idea is shared by Klein, who says, 

 referring to the animal cell : — " To every experienced 

 student of histology it must have become apparent that if 

 there is one thing unsatisfactory, unreliable, puzzling, and 

 inconstant about the nucleus of vast numbers of cells, it is 

 this very nucleolus." He concludes that the so-called 

 nucleoli are either thickenings of the intra-nuclear network, 

 or result from " shrivelling up and intimate fusion of a part 

 of the network." 



More recently Flemming, Treub, Schmidt, and Hegel- 

 maier have contributed some important observations. 

 Schmidt has shown * that in the cells of the Siplionem and 

 Siplionoclacle(€ among Algae, as also in Saprolegnia and the 

 Myxomycetes among fungi, instead of one nucleus, many 

 may be present ; amounting in the genus Valonia, for 

 instance, to several hundreds. He has further proved that 

 various of the simpler alg?e and fungi, formerly supposed 

 destitute of a nucleus, possess such a body ; and he con- 

 cludes that in all Thallophytes the cells contain one or more 

 nuclei, organisms destitute of a nucleus being unknown. 

 Treubf points out that not only in Cryptogams do a plurality 

 of nuclei occur, but that in the bast fibres and laticiferous 

 cells of various Phanerogams a like condition is found. 



Hegelmaier | records observations on the cells of the 

 suspensor in various leguminous plants, and states that in 

 these, numerous nuclei may be present, to the number of 

 twenty, thirty, or more, embedded in a parietal layer of 

 protoplasm. Inside each is a clearly-marked nucleolus ; 

 and in old nuclei two nucleoli may be found. He then 

 advances the important fact, which I had previously veri- 

 fied for myself in various plants, that division of the 

 nucleus is always preceded by that of the nucleolus, which 

 elongates, assuming a dumb-bell shape, and then divides. 

 The nucleus next divides, and one nucleolus goes with each 

 half. He notices that wdiile the nucleolus is sharp and clear 

 in outline, the nucleus at its periphery seems to fuse with 



* S. B. Niederrhein, "Geo. Natur-u Heilk." Bonn, 1879. 

 t Com-ptes Eendus, Ixxxix. 1879, page 494. 

 X Bot. Zeit. xxxviii. page 513. 

 TRANS. BOT. SOC. VOL. XIV. O 



