REJUVENESCENCE IN NATURE. 259 



D. RECONSTRUCTION WITH DIVISION OF THE CONTENTS 

 OF THE MOTHER-CELL INTO AN INDEFINITE NUMBER OF 

 DAUGHTER-CELLS. The cases to be mentioned here all 

 belong to the fructification of the Algae, Lichens, and 

 Fungi ; they have hitherto been included, especially by 

 Nageli, not under cases of cell-formation by division, 

 but of free cell-formation, from which, however, they are 

 essentially distinct. While, in free cell-formation, the 

 mother-cell, notwithstanding the formation of daughter- 

 cells taking place in it, preserves its own vitality, that is, 

 continues to exist as a living cell, consequently possesses, 

 in addition to the daughter-cells, vitally active contents 

 bounded by the persistent primordial utricle, and often 

 still furnished with a well-preserved nucleus; in the 

 cases to be examined here, as in all formation of daughter- 

 cells by division, the mother-cell dies at the very first 

 formation of daughter-cells : which is especially indicated 

 by the constant dissolution of the primordial utricle of 

 the mother-cell. The entire contents of the mother-cell, 

 at most with the exception of a watery fluid containing 

 but few organic constituents, become applied to the 

 formation of the daughter-cells, and not by actuaUy 

 existing daughter-cells gradually consuming it, but in 

 such a way that the whole contents (so far as available 

 for reconstruction) are divided among the daughter-cells 

 at the earliest definition of the boundaries of the latter. 

 Hence the cells do not originate with free bounding 

 surfaces, but in original' contact both with each other 

 and with the wall of the mother-cell; but they may 

 separate subsequently, or, if the watery contents of the 

 mother-cell are excluded from the new structure, even at 

 the first completion of their formation. 



1. The daughter-cells are formed by the division of 

 contents, filling the entire cavity of the mother-cell. 

 This case presupposes that the whole contents are 

 mucilaginous, and capable of sharing in the process of 

 reconstruction. 



a. The daughter-cells lie in one row in the mother- 



