CONTENTS. XV 



PAGE 



c. Relation of these phenomena to the interchange of 



substances in animals . . .217 



d. The nocturnal respiration of plants . . 219 



e. The phenomenon of Eejuvenescence of the Cell in 



its relation to the periods of the day . . 221 



3. Reconstruction of the Cell, considered as a process of Rejuve- 



nescence ..... 226 

 Kind and degree of Reconstruction : 



A. Reconstruction without division of the cell . . 229 



B. With division into two Daughter- cells . .232 

 (Different descriptions of this by Mohl, Unger, and Nageli) 233 



a. Division by gradual constriction (confirmed in Spi- 



rogyra) . . . . .237 



b. Division with simultaneous (?) limitation over the 



whole plane of division . . . 247 



B*. Reconstruction with division into two cells, one remaining 

 as an unchanged Mother-cell, the other cut off as a 

 Daughter-cell (cell-formation by constriction). . 250 



c. Reconstruction with division into four Daughter-cells . 254 

 Connection of this with halving . . .256 



D. Reconstruction with division into an indefinite number of 



Daughter-cells . . . .259 



1. By division of contents filling the whole cavity of the 



cell . . . . .259 



2. By division of a layer of contents investing the wall of 



the Mother-cell (explained specially in Hydrodictyon) 261 

 Connecting case . . . .271 



E. Partial Reconstruction through formation of Daughter-cells 



in the contents of the independently survivingMother-cell 272 



1. The Daughter-cells produced close upon the cell-wall 272 



2. The Daughter-cells formed free in the contents . 274 



a. Formation of a free Daughter-cell around the pri- 



mary nucleus of the Mother-cell . . 275 



b. Formation of free Daughter-cells around secondary 



- nuclei . . . .276 



. Formation of the germinal vesicles of the Pha- 



nerogamia .... 276 

 /3. Of the transitory cells in the embryo-sac . 278 

 y. Of the endosperm cells . . 278 



3. Cases of abnormal cell-formation . . 281 



4. Appendix, on the union of previously separate Cells (Con- 



jugation) ...... 281 



