BRITISH ASSOCIATION. 309 



himself, but at the present time few are misled. The student of 

 genetics knows that 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 Evolution 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 

 Evolution 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. Eor 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 have 

 only just 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 sure 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 postu- 

 lated as the basis of all evolutionary change. Do we then as a 

 matter of fact find in the world about us variations occurring of 

 such a kind as to warrant faith in a contemporary progressive 

 Evolution? Till lately most of us would have said "yes" without 

 misgiving. We should have pointed, as Darwin did, to the immense 



