44 PHILOSOPHICAL NOTES ON 



The fusion of germ and sperm cells as a factor of modification 

 is conceivable enough. The more varied are the parents of these 

 germs, the more variations are they likely to give rise to when 

 they conjugate. 



There is, however, another factor in modification, which may 

 not have attracted sufficient attention — I mean the fusion of two 

 alreadi/ con]\igSited pairs of germs. This fusion maybe either 

 complete or incomplete ; hence, among animals we have, as a 

 result, a lamb with two heads, two lambs with one head, a chicken 

 with four legs, or hands and feet with six digits, or two bodies 

 with one pair of legs, and so forth. It is even conceivable that 

 the symmetrical bodies of vertebrates and articulate animals may 

 have resulted from the fusion of two originally unsymmetrical 

 individuals during their foetal life. 



Of this mode of fusion as a factor in the variation of plants I 

 have treated elsewhere. In studying the beginnings of plants, 

 such as we see them in seaweeds, it is not difficult to see, in spite 

 of innumerable variations, that there is evolutionary progress from 

 the simple to the complex. 



It is now well understood that given " variations," whatever 

 their origin may have been, and unlimited reproduction, what is 

 called a " struggle for existence "* must ensue, and naturally the 

 " survival of the fittest "t will follow. 



The plants we see in the water and on land are the survivals 

 of the fittest, each in its own sphere. And the gaps between 

 these survivals are biological valleys in which myriads of the unfit 

 have been buried during the vast ages through which this 

 variation and struggle have been going on. Notwithstanding the 

 gaps, the survivals, or biological peaks are all related by a common 

 origin, which biologists consider to have been unicellular plants, 

 of which the modern representatives are descendants. 



To sum up then, in spite of the infinite variations we see in 

 ^11 directions in land plants, we also can note that there is a 

 sameness underlying all this variation, and this sameness we can 

 trace as low down as seaweeds. With a further use of the 



* This expression is ofteu used metaphorically, especially with reference to 

 plants. 



t This term " fittest " has a very broad meaning. 



