678 
aspects besides the obvious ones. Infant mortality 
we are asked to iament without the slightest thought 
of what the world would be like if the majority of 
these infants were to survive. The decline in the 
birth-rate in countries already over-populated is often 
deplored, and we are told that a nation in which 
population is not rapidly increasing must be in a de- 
cline. The slightest acquaintance with biology,: or 
even school-boy natural history, shows that this in- 
ference may be entirely wrong, and that before such 
a question can be decided in one way or the other, 
hosts of considerations must be taken into account. 
In normal stable conditions population is stationary. 
The laity never appreciates, what is so clear to a 
biologist, that the last century and a quarter, corre- 
sponding with the great rise in population, has been 
an altogether exceptional period. To our species this 
period has been what its early years in Australia were 
to the rabbit. The exploitation of energy-capital of 
the earth in coal, development of the new countries, 
and the consequent pouring of food into Europe, the 
application of antiseptics, these are the things that 
have enabled the human population to increase. I 
do not doubt that if population were more evenly 
spread over the earth it might increase very much 
more; but the essential fact is that under any stable 
conditions a limit must be reached. A pair of wrens 
will bring off a dozen young every year, but each year 
you will find the same number of pairs in your 
garden. In England the limit beyond which under 
present conditions of distribution increase of popula- 
tion is a source of suffering rather than of happiness 
has been reached already. Younger communities 
living in territories largely vacant are very probably 
right in desiring and encouraging more population. 
Increase, may, for some temporary reason, be essen- 
tial to their prosperity. But those who live, as I do, 
among thousands of creatures in a state of semi- 
starvation will realise that too few is better than too 
many, and will acknowledge the wisdom of Eccle- 
siasticus 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 com- 
munities—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 compara- 
tively 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 con- 
ditions 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 
‘“improvement’’ 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 appear- 
ance of a ‘‘thrashable’’ wheat. The ears of the wild 
wheats break easily to pieces, and the grain remains 
NO: 2330,; VOL;-93) 
NATURE 
[AUGUST 27, 1914 
| in the thick husk. Such wheat can be used for food, 
| but the true pioneer, 
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 brittle- 
ness is due, and the recessive, thrashable wheat re- 
sulted. Some man noticed this wonderful novelty, 
and it has been disseminated 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 civilisation been achieved ? 
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 civilised 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 almost say scores—of men, 
and on what plane of civilisation should we be? We 
should not have advanced beyond the medieval stage 
without printing, chemistry, steam, electricity, or 
surgery worthy the name. These things are the con- 
tributions 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 add nothing to universal progress. To improve 
by subordinate invention, to discover details missed, 
even to apply knowledge never before applied, all 
these things need genius in some degree, and are far 
beyond the powers of the average man of our race; 
the man whose penetration 
creates a new world, as did that of Newton and of 
Pasteur, is inconceivably rare. But for a few 
thousands of such men, we should perhaps be in the 
Paleolithic era, knowing neither metals, writing, 
arithmetic, weaving, nor pottery. 
In the history of art the same is true, but with 
this remarkable difference, that not only are gifts of 
artistic creation very rare, but even the faculty of 
artistic enjoyment, not to speak of higher powers of 
appreciation, is not attained without variation from 
the common type. I am speaking, of course, of 
the non-Semitic races of modern Europe, among 
whom the power whether of making or enjoying 
works of art is confined to an insignificant number 
of individuals. Appreciation can in some degree be 
simulated, but in our population there is no wide- 
spread physiological appetite for such things. When 
detached from the centres where they are made by 
others most of us pass our time in great contentment, 
making nothing that is beautiful, and quite uncon- 
scious of any deprivation. Musical taste is the most 
notable exception, for in certain races—for example, 
the Welsh and some of the Germans—it is almost 
universal. Otherwise artistic faculty is still sporadic 
in its occurrence. The case of music well illustrates 
the application of genetic analysis to human faculty. 
No one disputes that musical ability is congenital. 
In its fuller manifestation it demands sense of 
rhythm, ear, and_ special nervous and muscular 
powers. Each of these is separable and doubtless 
genetically distinct. Each is the consequence of a 
special departure from the common type. Teaching 
and external influences are powerless to evoke these 
faculties, though their development may be assisted. 
The only conceivable way in which the people of 
England, for example, could become a musical nation 
would be by the gradual rise in the proportional 
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