356 THE ZOOLOGIST. 



and will acknowledge the wisdom of Ecclesiasticus who said, " Desire 

 not a multitude of unprofitable children." 



But at least it is often urged that the decline in the birth-rate of 

 the intelligent and successful sections of the population — I am 

 speaking of the older communities — is to be regretted. Even this 

 cannot be granted without qualification. As the biologist knows, 

 differentiation is indispensable to progress. If population were 

 homogeneous, civilisation would stop. In every army the officers 

 must be comparatively few. Consequently, if the upper strata of the 

 community produce more children than will recruit their numbers 

 some must fall into the lower strata and increase the pressure there. 

 Statisticians tell us that an average of four children under present 

 conditions is sufficient to keep the number constant, and as the 

 expectation of life is steadily improving we may perhaps contemplate 

 some diminution of that number without alarm. 



In the study of history biological treatment is only beginning to 

 be applied. For us the causes of the success and failure of races are 

 physiological events, and the progress of man has depended upon a 

 chain of these events, like those which have resulted in the " im- 

 provement " of the domesticated animals and plants. It is obvious, 

 for example, that had the cereals never been domesticated cities 

 could scarcely have existed. But we may go further, and say that 

 in temperate countries of the Old World (having neither rice nor 

 maize) populations concentrated in large cities have been made 

 possible by the appearance of a " thrashable " wheat. The ears of 

 the wild wheats break easily to pieces, and the grain remains in the 

 thick husk. Such wheat can be used for food, but not readily. Ages 

 before written history began, in some unknown place, plants, or more 

 likely a plant, of wheat lost the dominant factor to which this 

 brittleness is due, and the recessive, thrashable wheat resulted. 

 Some man noticed this wonderful novelty, and it has been dis- 

 seminated over the earth. The original variation may well have 

 occurred once only, in a single germ-cell. 



So must it have been with Man. Translated into terms of factors, 

 how has that progress in control of nature which we call civilization 

 been achieved V By the sporadic appearance of variations, mostly, 

 perhaps all, consisting in a loss of elements, which inhibit the free 

 working of the mind. The members of civilized communities, when 

 they think about such things at all, imagine the process a gradual 

 one, and that they themselves are active agents in it. Few, however, 

 contribute anything but their labour ; and except in so far as they 

 have freedom to adopt and imitate, their physiological composition 

 is that of an earlier order of beings. Annul the work of a few 

 hundreds — I might say scores — of men, and on what plane of 

 civilisation should we be? We should not have advanced beyond 

 the mediaeval stage without printing, chemistry, steam, electricity, 

 or surgery worthy the name. These things are the contributions of 

 a few excessively rare minds. Galton reckoned those to whom the 

 term " illustrious " might be applied as one in a million, but in that 

 number he is. of course, reckoning men famous in ways which idd 



