Editorial 
3 
(ii.) TJie Spirit of Biometrika. 
It is almost impossible to study any type of life without being impressed by 
the small importance of the individual. In most cases the number of individuals 
is enormous, they are spread over wide areas, and have existed through long- 
periods. Evolution must depend upon substantial changes in considerable num- 
bers and its theory therefore belongs to that class of phenomena which statisticians 
have grown accustomed to refer to as mass-phenomena. A single individual may 
have a variation which fits it to survive, but unless that variation appears in many 
individuals, or unless that individual increases and multiplies without loss of the 
useful variation up to comparatively great numbers — shortly, until the fit type of 
life becomes a mass-phenomenon, it cannot be an effective foctor in evolution. 
The moment this point is grasped, then whether we hold variation to be con- 
tinuous or discontinuous in magnitude, to be slow or sadden in time, we recoonise 
that the problem of evolution is a problem in statistics, in the vital statistics of 
populations. Whatever views we hold on selection, inheritance, or fertility, we 
must ultimately turn to the mathematics of large number.^, to the theory of mass- 
phenomena, to interpret safely our observations. As we cannot follow the growth 
of nations without statistics of birth, death, duration of life, marriage and fertility, 
so it is impossible to follow the changes of any type of life without its vital 
statistics. The evolutionist has to become in the widest sense of the words a 
registrar-general for all forms of life. When he cannot observe and measure in 
Nature, then he must experiment on "populations" within the laboratory. But 
few biological laboratories have the space or the resources needed for dealing with 
the vital changes of populations, still less do the means at the disposal of indi- 
viduals suffice for carrying out extensive experiments of this character. Much has 
been done and undoubtedly more will be done by the Marine Biological Labora- 
tories for the study of mass-phenomena, but what is urgently needed is the estab- 
lishment of a well-equipped Biometric Farm Laboratory, where breeding and 
survival experiments on large numbers could be carried out with ample room 
and care and, when necessary, for long periods. To this point we hope to return, 
and we shall not cease to urge its importance*. 
But if we have thus to deal with a mass-phenomenon, may we not ask how it 
came about that the founder of our modern theory of descent made so little appeal 
to statistics ? An illustration may aid us ; the structure of our present theory of 
the moon is the creation of Newton, using his characteristic geometrical methods. 
But the practical astronomer in all lunar investigations to-day applies the analy- 
tical methods subsequently devised by the French mathematicians. The charac- 
teristic bent of Charles Darwin's mind led him to establish the theory of descent 
* The failure of an attempt in this direction made a few years ago was, we helieve, largely 
due to the fact that some of its supporters had not realised that the problem of evolution is a 
problem in the vital statistics of large numbers. 
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