116 



VEGETABLE CELLS. 



which has been formed as an after-growth in the cell. 

 We are acquainted with such secondary nuclei in the 

 parent-cells of spores and pollen-granules, and in the 

 spore- and pollen-cells themselves.* In these, however, 

 there is also a primary nucleus. The two nuclei lie side 

 by side in their cell ; or the primary nucleus becomes 

 dissolved when the secondary is produced. In the cases 

 referred to, the primary nucleus is parietal, the secondary 

 free. Now, as regards the nuclei in the germ-cells of the 

 Algae, Lichens, and Fungi, in some I found a distinctly 

 parietal position. I conjecture, therefore, already on these 

 grounds, that they are primary nuclei, and, consequently, 

 that a nucleus exists in the origin of the germ-cells. This 

 conjecture is supported by another reason. In the section 

 on the nucleus,! I demonstrated that if any conclusion 

 from analogy at all be permitted, it must be assumed that 

 every vegetable-cell possesses a nucleus, at least in the 

 early stages of its existence. It is, therefore, in the 

 highest degree probable that a nucleus is present in the 

 cell originating by normal cell-formation, and this at the 

 actual time of its origin. This argument is still further 

 borne out by the fact that sometimes, in plants where no 

 nucleus is visible in the formation of the germ-cells, all 

 the succeeding cells are developed under the influence of 

 nuclei. Now it seems to me very improbable here that 

 the vegetative cell-formation should take place through 

 nuclei, and the reproductive cell-formation without, that, 

 consequently, the lower cell-formation should present 

 greater complexity, and the higher be the more simple. 

 It is further to be remarked, that the assumption that 

 germ-cells originate like endosperm-cells around nuclei, 

 may be connected with the visible phenomena without 

 stretching any point. In both places, globules of muci- 

 lage first present themselves, which gradually enlarge, and 

 at last appear as granular cells. In the endosperm-cells, 

 the nuclei may be distinguished and recognised as such, 



* Part I, Ray Translation, p. 247. $ Ibid., pp. 219 et seq., and 246. 



