332 SEA-SIDE STUDIES. 



the fluid. It tlien divides into two cells perfectly 

 similar. These two cells divide into four, eight, 

 sixteen, and so the multiplication continues, till there 

 is a filament of cells, each independent and capable of 

 separate existence, but each attached to the other by 

 its cell-wall. In a similar way leaves, instead of fila- 

 ments, are formed. Many of the lower plants are 

 nothing but aggregations of such cells ; and in many 

 this simple mode of Eeproduction is the only mode 

 yet discovered. By this j^rocess of subdivision a single 

 cell of the Protococcus nivalis (or red snow) will 

 redden vast tracts of snow in a few hours ; and the 

 Bovista giganteiim is estimated to produce in one 

 hour no less than four thousand millions of cells." 

 Ehrenberg computes the increase of the infusorial 

 Paramecium at two hundred and sixty-eight millions 

 in a month. In this, the simplest form of Reproduc- 

 tion, the identity of the process with that of Growth 

 is indisputable and undisputed. 



The whole organism consists of a simple cell, or 

 string of such cells : we must therefore either deny 

 that the union of two dissimilar cells is the essential 

 process of Generation, or we must j^oint-blank deny 

 that these cellular organisms are generated at all. If, 

 shrinking from this latter alternative, we acknowledge 

 that Generation must take place in these organisms, 

 how shall we establish a line of demarcation between 

 the reproduction of independent ceUs, and that of cells 

 united together in a filament ? In other words, how 

 shall we demarcate Reproduction from Growth ? When 



