34 PRESIDENT’S ADDRESS. 
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 produced by that age Galton estimated the 
average intelligence 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 recognis- 
able 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 integrity 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 derived. Sporadi- 
cally 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 presumably pur- 
suing 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 century came the ‘ reforms’ of Cleisthenes 
(507 B.c.), which sanctioned foreign marriages and admitted to citizen- 
ship a number not only of resident aliens but also of manumitted 
slaves. As Aristotle says, Cleisthenes legislated with the deliberate 
purpose of breaking up the phratries and gentes, in order that the 
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 beginning 
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 3.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 mongrelised. 
Let me not be construed as arguing that mixture of races is an 
° For tables of families, see the Supplement to Who’s Who in the Theatre. 
