CELL-FORMATION. 135 



Schleiden was the first to express the formation of cells 

 in cells as the universal law for vegetables. In many 

 researches on the most diverse orders of the vegetable 

 kingdom, and on the most varied organs of plants, I have 

 never met with the formation of cells outside cells. Minute 

 investigation in the proper stages of development always 

 shows that the new cells proceed from parent-cells. 



Meyen,* indeed, makes a portion of the cellular tissue 

 of the young anther become dissolved, and new cells to 

 originate in the homogeneous mucilage. But I have 

 shown that Meyen mistook a very thin, delicate tissue 

 for amorphous mucilage.f 



Mirbel j considers that the cambium in the root of the 

 Date-palm consists of an amorphous, homogeneous, thick 

 fluid,in which the cells are formed. But in the roots of 

 the Date-palm, as in all other cambium in entire sections, 

 I find a continuous cellular tissue, and never any inter- 

 ruption by an amorphous mass. 



Schleiden came to a similar result with regard to the 

 cell-formation in cambium. 



Endlicher and Unger || recently affirm cells to originate 

 also through intercellular formation, appearing first as 

 cavities in the intercellular substance, and acquire proper 

 walls subsequently through the condensation of the latter. 

 But if cells lie in a gelatinous mass, this is by no means 

 a proof that they have originated in this. The history of 

 development must decide whether the cells have been 

 produced from the gelatinous mass, or the gelatine from 

 the cells. My researches on the Algae and Fungi show 

 to me that, without exception, the cells exist first, and 

 the gelatinous matter which subsequently surrounds them 

 is produced by the cells. In the simple plants, such as 

 Nostoc, Palmella, &c., the development may be traced 

 from the very first cell. In the more complicated plants, 



* Physiologic, Band iii, 119 ; pi. xii, fig. 2. 



Zur Eritwickelungsgesch. des Pollens, p. 10, figs. 2-7, 31-36, 47, 48. 

 \ Nouvelles notes sur le Cambium ; Archiv de Museum, tome i, pi. xxi. 

 Grundziige d. wiss Bot. 1st Ed. vol. i, p. 199. 

 j| Grundz. der Botanik, p. 33. 



