20 



1832. He was at least the first botanist who recognised the 

 importance of the facts from which we might conclude with 

 certainty on the increase of the cells by separation ; and M. 

 Mohl has noticed this important subject more fully in Con- 

 ferva glomerata. Suppositions and simple conjectures that 

 cells increased in such a way had frequently been given out, 

 but there is a very great difference between the origin of new 

 cells in the way stated, and the formation of the pollen vesicles, 

 which originate in a manner similar to the albumen of seeds, 

 and M. Morren can hardly lay claim to the discovery of these 

 facts. It was well known for instance that all the cells in a 

 Conferva, proceed from the few cells of the spore, but never- 

 theless we did not then know in what manner the increase 

 of the cells took place ; we were acquainted with the elongation 

 of the spores in severalHyphomyceteSyand the extension of these 

 spores to the development of the young plant ; but yet we had 

 no distinct idea of the process contemporaneously in action. 



M. Morren has since then continued his observations on the 

 separation of the cells in the Conferva, and thinks he has suc- 

 ceeded in recognising in Conferva dissiliens all the circum- 

 stances at the formation of the diagonal partitions ; he observed 

 in this plant that the cells were elongated, and the mass therein 

 contained was divided in the centre into two parts by a trans- 

 parent free space, which was formed of a mucous fluid, which 

 from its destination he supposes to be an intercellular sub- 

 stance, and names it inter-chromula (inter- or meta-chromu- 

 laire or Metendockromique). The condensation now begins 

 from the periphery of this substance, by which the union with 

 the common cell is at the same time effected, and as this ad- 

 vances more and more towards the centre, the double mem- 

 brane thus formed takes the place of the transparent fluid sub- 

 stance, so that now each single portion of the endochrom pos- 

 sesses its distinct membrane. 



M. Dutrochet's memoir on the respiration of plants, which 

 was but shortly noticed in last year's report, p. 56*, has since 

 been published entire t ; the results of this work coincide how- 

 ever very little with the views of many other physiologists, 



* Page 536 of the translation in the Lond. and Edinb. Philosophical Ma- 

 gazine for Dec. 1837. TRANSL. 



f Recherches sur les organes pneumatiques et sur la respiration des v6- 

 getaux. In the collective edition of the Memoirs of M. Dutrochet, i. p. 320. 



