PRESIDENT’S ADDRESS. 11 
the time for the development of theory is not yet. He would rather 
stick to the seed-pan and the incubator. 
In face of what we now know of the distribution of variability in 
nature the scope claimed for Natural Selection in determining the fixity 
of Species must be greatly reduced. The doctrine of the survival of the 
fittest is undeniable so long as it is applied to the organism as a whole, 
but to attempt by this principle to find value in all definiteness of parts 
and functions, and in the name of Science to see fitness everywhere 
is mere eighteenth-century optimism. Yet it was in application to the 
parts, to the details of specific difference, to the spots on the peacock’s 
tail, to the colouring of an Orchid flower, and hosts of such examples, 
that the potency of Natural Selection was urged with the strongest 
emphasis. Shorn of these pretensions the doctrine of the survival of 
favoured races is a truism, helping scarcely at all to account for the 
diversity of species. Tolerance plays almost as considerable a part. 
By these admissions almost the last shred of that teleological fustian 
with which Victorian philosophy loved to clothe the theory of Evolu- 
tion is destroyed. Those who would proclaim that whatever is is right 
will be wise henceforth to base this faith frankly on the impregnable 
rock of superstition, and to abstain from direct appeals to natural fact. 
My predecessor said last year that in physics the age is one of rapid 
progress and profound scepticism. In at least as high a degree this is 
true of Biology, and as a chief characteristic of modern evolutionary . 
thought we must confess also to a deep but irksome humility in 
presence of great vital problems. Every theory of Hvolution must be 
such as to accord with the facts of physics and chemistry, a primary 
necessity to which our predecessors paid small heed. For them the 
unknown was a rich mine of possibilities on which they could freely 
draw. For us it is rather an impenetrable mountain out of which the 
truth can be chipped in rare and isolated fragments. Of the physics and 
chemistry of life we know next to nothing. Somehow the characters 
of living things are bound up in properties of colloids, and are largely 
determined by the chemical powers of enzymes, but the study of these 
classes of matter has only fust begun. Living things are found by a 
simple experiment to have powers undreamt of, and who knows what 
may be behind? 
Naturally we turn aside from generalities. It is no time to discuss 
the origin of the Mollusca or of Dicotyledons, while we are not even 
gure how it came to pass that Primula obconica has in twenty-five years 
produced its abundant new forms almost under our eyes. Knowledge 
of heredity has so reacted on our conceptions of variation that very 
competent men are even denying that variation in the old sense is a 
genuine occurrence at all. Variation is postulated as the basis of all 
evolutionary change. Do we then as a matter of fact find in the world 
