860 REPRODUCTION, DEVELOPMENT, GROWTH AND DEATH [CH. LIX. 



the scientific mind, for it is one which is susceptible of proof and 

 demonstration. It may be best illustrated by a concrete example. 

 If two kinds of plant, such as dwarf and tall peas, are crossed, the 

 seeds obtained all produce tall plants; but if the plants of this 

 generation are crossed, the third generation contains 25 per cent, 

 dwarf and 75 per cent, of tall plants. If the dwarfs are crossed, 

 they breed true, that is, they produce dwarf plants only ; but if the 

 tali plants are inter-crossed, again one-quarter of the next generation 

 are dwarfs and the remainder tall. Of the 75 tall plants, 25 breed 

 true, and of the remaining 50, one-quarter produce dwarfs which 

 breed true, and the remaining three-quarters are tall plants. In 

 successive generations the same holds : the dwarfs, when self-crossed, 

 always produce dwarfs, and tall plants always produce a progeny in 

 which 25 per cent, are dwarfs and 75 per cent, tall, some of which 

 breed true and the remainder breed a mixture in the same pro- 

 portions as before. 



This is explained by calling certain characters dominant 

 and others recessive; thus, in the example taken, tallness is 

 dominant and dwarfness is recessive. So in the first generation the 

 progeny all exhibit the dominant character, but in the second only 

 25 per cent, will be pure dominants (that is, will produce only 

 dominants in successive generations), 25 per cent, will be pure 

 recessives, and 50 per cent, are mixed; and the mixed type will 

 again produce 25 per cent, dominants, 25 per cent, recessives, and 

 50 per cent, mixed, as before. 



This discovery has been found important for breeders and 

 horticulturists, but the law appears to fail sometimes; for instance, 

 when the black and white races intermarry, the result is brown 

 children, and not a definite proportion of blacks and whites. 



Looked at from the evolutionary point of view, the whole of the 

 complex animal body is but the temporary dwelling-place of the 

 reproductive cells, and nature provides lavishly, both in animals and 

 plants, for the continuance of the species. These temporary homes, 

 which we call the father and the mother, pass away, but they live on 

 and on in their descendants. In the future we cannot doubt that 

 upward progress will still continue as in the past, and man in time 

 should be in very truth " but little lower than the angels." Some 

 hold that civilisation in some ways places a slight obstacle on the 

 path of progress of the race; numerous works of charity militate 

 against the inexorable law of the survival of the fittest, so that 

 many live to propagate their species who may be weaklings both in 

 body and mind. There are no doubt extreme cases where it is 

 desirable that deteriorated characters should be debarred from 

 introducing into the world a continuance of beings destined for 

 misery and crime. But I myself believe that the present development 



