rii^ 



190 



THE BEGINNINGS OF LIFE. 



J 



cell.' I have also, of late, since having become ac- 

 quainted with these observations of 



of Mr. Carter, re- 

 peatedly watched the formation of independent cells 

 of this kind within the filaments of Vmchena — resulting 

 from modifications taking place in what were at first 

 irregular masses of protoplasm containing chlorophyll 

 granules. A definite cell-wall is soon formed around 

 these variously-sized masses^ whilst the most striking 

 changes also take place in the substance of the newly 

 constituted cell. These changes, however, will be more 

 fully described in a later chapter. 



Hitherto we have been speaking of Cryptogamic 

 plants, but through the admirable researches of Hof- 

 meister ^ we know that just as good instances of ^ free ' 

 cell formation are to be met with amongst the Pha- 

 nerogamia, or o dinary flowering plants. The inves- 



tigation of the subject 



here, is however much more 



difficult for the observer. There is this difference also, 

 with these more complicated plants, that the embryo-sac, 

 or mother-cell, itself persists for a time, instead of being 

 destroyed by the reproductive process. We will quote 



the 



description given 



by Braun^ of the phenomena 

 taking place during the formation of the seed in one 

 of the flowering plants. He says : — ^ The embryo-sac, 



as it is termed, is the last cell of the 

 mother plant, the uppermost in the axial row of cells 

 of the ovule, destined to become the focus of re- 



or germ-sac, 



1 ( 



Der Enstehung des Embryos der Phanerogamen/ 1849. 



^ Loc. cit, p. 276. 



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