314 SEA-SIDE STUDIES. 



less than four thousand millions of cells. Ehrenberg com- 

 putes the increase of the infusorial Paramecium at two 

 hundred and sixty-eight millions in a month. In this, the 

 simplest form of Reproduction, 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 point-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 cells, and that of 

 cells miited together in a filament ? In other words, how 

 shall we demarcate Reproduction from Growth ? When the 

 cells are attached, a filament is fonned, and the plant is said 

 to grow ; when the cells are detached, a new plant is said to 

 be generated : but whatever differences there may be 

 between twenty cells forming a filament, and twenty ceDs 

 existing separately, each capable of growing into a filament, 

 the origin of both is one and the same, and the process of 

 Growth is identical with the process of Generation. 



In a fonner passage I suggested that it was probably 

 owing to difierences of temperature, or food, that Reproduc- 

 tion by Gemmation and by Generation took place. This, 

 which was hypothetical as regards the Polype, can be demon- 

 strated in the Yeast plant. There are two kinds of yeast, or 

 rather two forms of the same plant. The one is called surface 

 yeast, the other sediment yeast. The former requires a tem- 



