AvuGUST 27, 1914] 
numbers of a musical strain or strains until the 
present type became so rare as to be negligible. It 
by no means follows that in any other respect the 
resulting population would be distinguishable from 
the present one. Difficulties of this kind beset 
the efforts of anthropologists to trace racial 
origins. It must continually be remembered that most 
characters are independently transmitted and capable 
of such recombination. In the light of Mendelian 
knowledge the discussion whether a race is pure or 
mixed loses almost all significance. A race is pure 
if it breeds pure and not otherwise. Historically we 
may know that a race like our own was, as a matter 
of fact, of mixed origin. But a character may have 
been introduced by a single individual, though sub- 
sequently it becomes common to the race. This is 
merely a variant on the familiar paradox that in the 
course of time if registration is accurate we shall all 
have the same surname. In the case of music, for 
instance, the gift, originally perhaps from a Welsh 
source, might permeate the nation, and the question 
would then arise whether the nation, so changed, 
was the English nation or not. 
Such a problem is raised in a striking form by 
the population of modern Greece, and especially of 
Athens. The racial characteristics of the Athenian 
of the fifth century B.c. are vividly described by Galton 
in ‘‘ Hereditary Genius.”” The fact that in that period 
a population, numbering many thousands, should 
have existed, capable of following the great plays 
at a first hearing, revelling in subtleties of speech, 
and thrilling with passionate delight in beautiful 
things, is physiologically a most singular phenomenon. 
On the basis of the number of illustrious men pro- 
duced by that age Galton estimated the average in- 
telligence as at least two of his degrees above our 
own, differing from us as much as we do from the 
negro. A few generations later the display was over. 
The origin of that constellation of human genius 
which then blazed out is as yet beyond all biological 
analysis, but I think we are not altogether without 
suspicion of the sequence of the biological events. 
If I visit a poultry-breeder who has a fine stock of 
thoroughbred game fowls breeding true, and ten years 
later—that is to say ten fowl-generations later—I go 
again and find scarcely a recognisable game-fowl on 
the place, I know exactly what has happened. One 
or two birds of some other or of no breed must have 
strayed in and their progeny been left undestroyed. 
Now in Athens we have many indications that up to 
the beginning of the fifth century so long as the 
phratries and gentes were maintained in their in- 
tegrity there was rather close endogamy, a condition 
giving the best chance of producing a homogeneous 
population. There was no lack of material from 
which intelligence and artistic power might be de- 
rived. Sporadically these qualities existed throughout 
the ancient Greek world from the dawn of history, 
and, for example, the vase-painters, the makers of the 
Tanagra figurines, and the gem-cutters were presum- 
ably pursuing family crafts, much as are the actor- 
families? of England or the professorial families of 
Germany at the present day. How the intellectual 
strains should have acquired predominance we cannot 
tell, but in an in-breeding community homogeneity at 
least is not surprising. At the end of the sixth cen- 
tury came the ‘‘reforms”’ of Cleisthenes (507 B.c.), 
which sanctioned foreign marriages and admitted to 
citizenship a number not only of resident aliens but 
also of manumitted slaves. As Aristotle says, Cleis- 
thenes legislated with the deliberate purpose of break- 
ing up the phratries and gentes, in order that the 
2 For tables of these families, see the Supplement to ‘“‘ Who's Who in the 
Theatre.” 
NO. 2339, VOL. 93] 
NATURE 
679 
various sections of the population might be mixed up 
as much as possible, and the old tribal associations 
abolished. The ‘‘reform’’ was probably a recognition 
and extension of a process already begun; but is it too 
much to suppose that we have here the effective be- 
ginning of a series of genetic changes which in a 
few generations so greatly altered the character of 
the people? Under Pericles the old law was restored 
(451 B.c.), but losses in the great wars led to further 
laxity in practice, and though at the end of the fifth 
century the strict rule was re-enacted that a citizen 
must be of citizen-birth on both sides, the population 
by that time may well have become largely mon- 
grelised. 
Let me not be construed as arguing that mixture 
of races is an evil: far from it. A population like 
our own, indeed, owes much of its strength to the 
extreme diversity of its components, for they con- 
tribute a corresponding abundance of aptitudes. 
Everything turns on the nature of the ingredients 
brought in, and I am concerned solely with the obser- 
vation that these genetic disturbances lead ultimately 
to great and usually unforeseen changes in the nature 
of the population. 
Some experiments of this kind are going on at the 
present time, in the United States, for example, on a 
very large scale. Our grand-children may live to see 
the characteristics of the American population entirely 
altered by the vast invasion of Italian and other South 
European elements. We may expect that the Eastern 
States, and especially New England, the people of which 
still exhibit the fine Puritan qualities with their appro- 
priate limitations, absorbing little of the alien 
elements, will before long be in feelings and aptitudes 
very notably differentiated from the rest. In Japan, 
also, with the abolition of the feudal system and the 
rise of commercialism, a change in population has 
begun which may be worthy of the attention of 
naturalists in that country. Till the revolution . the 
Samurai almost always married within their own 
class, with the result, as I am informed, that the caste 
had fairly recognisable features. The changes of 
1868 and the consequent impoverishment of the 
Samurai have brought about a beginning of dis- 
integration which may not improbably have perceptible 
effects. 
How many genetic vicissitudes has our own peerage 
undergone! Into the hard-fighting stock of medieval 
and Plantagenet times have successively been crossed 
the cunning shrewdness of Tudor statesmen and 
courtiers, the numerous contributions of Charles II. 
and his concubines, reinforcing peculiar and persistent 
attributes which popular imagination especially re- 
gards as the characteristic of peers, ultimately the 
heroes of finance and industrialism. Definitely intel- 
lectual elements have been sporadically added, with 
rare exceptions, however, from the ranks of lawyers 
and politicians. To this aristocracy art, learning, and 
| science have contributed sparse ingredients, but these 
mostly chosen for celibacy or childlessness. A  re- 
markable body of men, nevertheless; with an average 
‘“horse-power,” as Samuel Butler would have said, 
far exceeding that of any random sample of the 
middle-class. If only man could be reproduced by 
budding what a simplification it would be! In vege- 
tative reproduction heredity is usually complete. The 
Washington plum can be divided to produce as many 
identical individuals as are required. If, say, Wash- 
ington, the statesman, or preferably King Solomon, 
could similarly have been propagated, all the nations 
of the earth could have been supplied with ideal 
rulers. 
Historians commonly ascribe such changes as 
occurred in Athens, and will almost certainly come 
