156 THE EVOLUTION THEORY 



cell up to the whole would remain wholly unexplained. The whole 

 crop of spontaneous germ-variations, whenever it ceases to be 

 ' indifferent,' and becomes either ' good ' or ' bad,' comes under the 

 shears of personal selection and under its almost sovereign sway. 



On the other hand, the sudden first appearance of a saltatory 

 variation takes place quite independently of personal selection, 

 depending on similar variations in a number of ids, which remain 

 latent until they have by the process of reducing division which 

 precedes amphimixis, chanced to attain a majoiity. In sudden bud- 

 variations we may perhaps suppose that reducing division occurring 

 in some still unverified abnormal manner is the reason why the 

 germinal variation suddenly makes itself visible— a supposition pre- 

 viously suggested as the explanation of the reversion of these sports. 



The rarity of bud-variation is thus explained, while the greater 

 frequency of saltatory variations in plants propagated by seed may 

 be accounted for by the regular occurrence of reducing division 

 in sexual reproduction. But that the same or similar variations 

 may occur in several, it may be in many, ids at the same time must 

 depend upon similar general influences which affect the plant as 

 a whole, as happens through cultivation, manuring, and so on. I shall 

 return to this when discussing the influence of the environment. 



In some quarters this whole conception of germinal selection has 

 been characterized as the merest figment of imagination, condemned 

 on this ground alone, that it is based on the differences in nutrition 

 between such extremely minute quantities of substance as the 

 chromosomes of nuclear substance within the germ-cell. The quantity 

 of substance is certainly minute, but it needs nutriment none the 

 less, and can we believe that the stream of nourishment for all 

 the invisibly minute vital elements is exactly alike 1 It may be 

 admitted that the nourishment outside the ids is usualljr abundant, 

 although undoubtedly fluctuations occur in it also, but it certainly 

 does not follow from this that every vital unit within the id is 

 similarly disposed in relation to the nutritive supply, or has food 

 in equal quantities at its command, or even that each has as much 

 as it can ever need. To make an assertion like this seems to me 

 much the same as if an inhabitant of the moon, lookincf at this earth 

 through an excellent telescope and clearly descrying the city of 

 Berlin with its thronging crowds and its railways bringing in the 

 necessaries of life from every side, should conclude from this abundant 

 provision that the greatest superfluity prevailed within the town, 

 and that every one of its inhabitants had as much to live iipon 

 as he could possibly require. 



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