TRANSACTIONS OF SECTION D. 579 
properties of organisms, We come upon these limits in various unexpected places, 
and to the naturalist ignorant of breeding nothing can be more surprising or 
instructive. 
Whatever be the mode of origin of new types, no theoretical evolutionist 
doubts that Selection will enable him to fix his character when obtained. Let 
him put his faith into practice. Let him set about breeding canaries to win in 
the class for Clear Yellow Norwich at the Crystal Palace Show. Being a selec- 
tionist, his plan will be to pick up winning yellow cocks and hens at shows and 
breed them together. The results will be disappointing. Not getting what he 
wants, he may buy still better clear yellows and work them in, and so on till his 
funds are exhausted, but he will pretty certainly breed no winner, be he never so 
skilful. For no selection of winning yellows will make them into a breed. They 
must be formed afresh by various combinations of colours appropriately crossed 
and worked up. Though breeders differ as to the system of combinations to be 
followed, all would agree that selection of birds representing the winning type 
was a sure way to fail. The same is true for nearly all canary colours except 
in Lizards, and, I believe, for some pigeon and poultry colours also, 
Let this scientific fancier now go to the Palace Poultry Show and buy the 
winning Brown Leghorn cock and hen, breed from them, and send up the result of 
such a mating year after year. His chance of a winner is not quite, but almost 
nil, For in its wisdom the fancy has chosen one type for the cock and another 
for the hen. They belong to distinct strains, The hen corresponding to the 
winning cock is too bright, and the cock corresponding to the winning hen is too 
dull for the judge’s taste. The same is the case in nearly every breed where the 
sex-colours differ markedly, Rarely winners of both sexes have come in one 
strain—a phenomenon I cannot now discuss—but the contrary is the rule. Does 
anyone suppose that this system of ‘double mating’ would be followed, with 
all the cost and trouble it involves, if Selection could compress the two 
strains into one? Yet current theory makes demands on Selection to which this 
is nothing. 
The tyro has confidence in the power of Selection to fix type, but he never 
stops to consider what fixation precisely means. Yet a simple experiment will 
tell him. He may go to a great show and claim the best pair of Andalusian fowls 
for any number of guineas. When he breeds from them he finds, to his disgust, 
that only about half their chickens, or slightly more, come blue at all, the rest 
being blacks or splashed whites. Indignantly, perhaps, he will complain to the 
vendor that he has been supplied with no selected breed, but worthless mongrels. 
In reply he may learn that beyond a doubt his birds come from blues only in the 
direct line for an indefinite number of generations, and that to throw blacks and 
splashed whites is the inalienable property of blue Andalusians. But now let him 
breed from his ‘ wasters,’ and he will find that the extracted blacks are pure and 
give blacks only, that the splashed whites similarly give only whites or splashed 
whites—but if the two sorts of ‘ wasters’ are crossed together blues only will 
result. Selection will never make the blues breed true; nor can this ever come to 
pass unless a blue be found whose germ-cells are bearers of the blue character— 
which may or may not be possible. If the selectionist reflect on this experience 
he will be led straight to the centre of our problem. There will fall, as it were, 
scales from his eyes, and in a flash he will see the true meaning of fixation of type, 
variability, and mutation, vaporous mysteries no more, 
Owing to the unhappy subdivisions of our studies, such phenomena as these— 
constant companions of the breeder—come seldom within the purview of modern 
science, which, forced for a moment to contemplate them, expresses astonishment 
and relapses into indolent scepticism. It is in the hope that a little may be done 
to draw research back into these forgotten paths that I avail myself of this great 
opportunity of speaking to my colleagues with somewhat wider range of topic 
than is possible within the limits of a scientific paper. For I am convinced that 
the investigation of heredity by experimental methods offers the sole chance of 
progress with the fundamental problems of evolution. 
PP2 
