REJUVENESCENCE IN NATURE. 275 



D. 2 {Ascidium, Cladophord). Free cell-formation in the 

 second sense, in which it was used for instance by 

 Nageli,* likewise comprehends two very different series 

 of cases, viz., either the origin is only so far free, that the 

 daughter-cells formed through the transformation of the 

 whole contents of the mother-cell (with or without division 

 of them), separate at the very moment of their consti- 

 tution, from the membrane of the mother-cell, by con- 

 traction of their mass, and separate from each other in 

 the same manner, as we have already examined under 

 A. 2 (formation of spores of (Edogonium), d. 2 {Sphmro- 

 jjlea) ; or the origin is free even in relation to the 

 definition of the boundaries of the original mass of con- 

 tents from which the new cell is formed, the daughter- 

 cells being formed, not out of the whole contents of the 

 mother-cell, but out of the separate, unconnected portions 

 of them. It is this last series of cases that especially 

 merits the name of free cell-formation, if this term is to 

 be retained; and then the circumstances whether the newly- 

 formed cells are applied upon the mother-cell (e. 1)^ or 

 not, — and, in like manner, whether they subsequently 

 become connected together into a continuous tissue (as 

 we shall see in the endosperm-cells), or not, — 'are to be 

 regarded as less essential. 



a, A free daughter-cell is formed around the primary 

 nucleus of the mother-cell.-^The case here mentioned 

 differs from those examined under a. 2, e.g. the formation 

 of the pollen-grain in its special mother-cell, in the cir- 

 cumstance that the daughter-cell does not take in the 

 whole of the contents of the mother-cell, but lies free in 

 the contents of the latter, so that other daughter-cells 

 may subsequently originate in the contents of the same 

 mother-cell. This strange and most rare case was 



* 'Zeitschrift,' 1846, p. 51, (Ray Translation, 1849, p. 123,) "Tn/ree 

 cell-formation a greater or smaller portion of the contents becomes isolated, or 

 even the whole contents of the cell. On the surface of this is formed a complete 

 membrane, altogether free at its outer surface, (in contact neither with the 

 wall of the mother-cell nor those of its sister-cells*)" 



