390 THE EVOLUTION OF MAN. 



and a growth of the organism beyond the individual size, 

 which, therefore, raises a part of the organism to the rank 

 of a whole (vol. i. p. 159). This is most clearly seen by 

 observing the reproduction of the simplest and lowest 

 organisms, especially of the Monera (p. 46) and of the one- 

 celled Amoeba (p. 48). In these, the simple individual pos- 

 sesses only the form -value of a single plastid. As soon as, 

 by continued nutrition and simple growth, this has reached 

 a certain size, it does not exceed that size, but falls, by 

 simple division, into two similar halves. Each of these 

 two halves thenceforth leads an independent life, and again 

 grows, till, having reached the same limit of growth, it once 

 more divides. At each of these simple self-divisions, two 

 new central points of attraction for the particles of the 

 body are formed, as foundations of the two new indi- 

 viduals.^^* 



In many other Primitive Animals {Protozoa), the simple 

 reproduction is accomplished, not by division, but by the 

 formation of buds (gemmation). In this case, the growth, 

 which prepares the way for reproduction, is not total (as in 

 the case of division), but partial. Hence in the case of 

 gemmation, the product of local growth, which, as a bud, 

 forms a new individual, can be distinguished, as a young 

 individual, from the parent-organism from which it 

 originates. The latter is older and larger than the former. 

 In the case of division, on the contrary, the two products 

 are of equal age and of equal form-value. Further 

 differentiated forms of asexual reproduction, connected 

 with gemmation, are, thirdly, the formation of germ-buds, 

 and, fourthly, the formation of germ-cells. The latter, 

 however, brings us directly to sexual reproduction, for which 



