ARTIFICIAL SELECTION 105 



the nonadaptive characters, and respond more readily to the 

 conditions of panmixia or of reversal of selection. 



In matters of breeding we must distinguish between animals 

 actually best and those potentially best. An animal is at its 

 actual best when in prime condition, at the prime of its life. 

 Another of far finer heredity, of far stronger ancestry, may be 

 at any given time actually the inferior of the first. It may be 

 too old, too young, in too poor condition to represent its own 

 best status. 



It is generally recognized that, for all breeding purposes, the 

 animal potentially best is superior to one which, otherwise 

 inferior, may be actually best at the time. The tendency of 

 heredity is to repeat the traits of the ideal individuals, which 

 the parents ought to have been. More exactly, the tendency of 

 heredity is to produce individuals which, under like conditions 

 of food and environment, would develop as the parents have 

 developed. 



But it is also recognized that the actual physical condition of 

 the parent affects the offspring. A sick mother is likely to bear 

 an enfeebled child. Immature or declining sires do not beget 

 offspring as strong as those begotten by them when they are in 

 perfect strength and health. In this matter, apparently, we have 

 to deal with two different elements, as Weismann and others have 

 pointed out. The first is true heredity, the quality of the germ cell, 

 which is not affected by the condition of the parent. Weak or 

 strong, the offspring is of the same kind or type as the parentage. 



The second element has been called Transmission. Its 

 relations are with vegetative development. The embryo is ill 

 nourished by the sick mother, and it enters on life with lowered 

 vigor. The momentum, if we may use such a figure of speech, 

 is reduced from the first, and the lost vitality may never be 

 regained. The defects of the male parent are perhaps of less 

 moment, but whatever their nature their results would be of 

 the same kind. They would not enter into the heredity of the 

 offspring, but they might play a large part in retarding its 

 development. In the category of transmission, not of heredity, 

 would belong the theme of Ibsen's " Ghosts" (Gjengangere) , the 

 development of softening of the brain in the son of a debauchee, 

 the alleged cause being that the father's nervous system was 

 vermoulu (worm-eaten), if we are to accept the ghastly drama 

 as an exposition of possible facts. 



