TRANSACTIONS OF SECTION D. 577 
whatever character the attention be fixed, whether size, number, form of the whole 
or of the parts, proportion, distribution of differentiation, sexual characters, 
fertility, precocity or lateness, colour, susceptibility to cold or to disease—in short, 
all the kinds of characters which we think of as best exemplifying specific 
difference, we are certain to find illustrations of the occurrence of departures from 
normality, presenting exactly the same definiteness elsewhere characteristic of 
normality itself, Again and again the circumstances of their occurrence render it 
impossible to suppose that these striking differences are the product of continued 
selection, or, indeed, that they represent the results of a gradual transformation of 
any kind. Whenever by any collocation of favouring circumstances such definite 
novelties possess a superior viability, supplanting their ‘normal’ relatives, it is 
obvious that new types will be created: 
The earliest statement of this simple inference is, I believe, that of Marchant,’ 
who in 1719, commenting on certain plants of Mercurialis with laciniated and 
hair-like leaves, which for a time established themselves in his garden, suggested 
that species may arise in like manner. Though the same conclusion has appeared 
inevitable to many, including authorities of very diverse experience, such as Huxley, 
Virchow, F’. Galton, it has been strenuously resisted by the bulk of scientific opinion, 
especially in England. Lately, however, the belief in Mutation, as De Vries has 
taught us to call it, has made notable progress,” owing to the publication of his 
splendid collection of observations and experiments, which must surely carry 
conviction of the reality and abundance of Mutation to the minds of all whose 
judgments can be affected by evidence. 
That the dread test of Natural Selection must be passed by every aspirant to 
existence, however brief, isa truism which needs no special proof. Those who 
find satisfaction in demonstrations of the obvious may amply indulge themselves 
by starting various sorts of some annual, say French poppy, in a garden, letting 
them run to seed, and noticing in a few years how many of the finer sorts are 
represented ; or by sowing an equal number of seeds taken from several varieties 
of carnation, lettuce, or auricula, and seeing in what proportions the fine kinds 
survive in competition with the common. 
Selection is a true phenomenon; but its function is to select, not to create. Many 
a white-edged poppy may have germinated and perished before Mr. Wilks saved 
the individual which in a few generations gave rise to the-Shirleys. Many a 
black Amphidasys betularta may have emerged before, some sixty years ago, in the 
urban conditions of Manchester the black var. doubledayaria found its chance, 
soon practically superseding the type in its place of origin, extending itself over 
England, and reappearing even in Belgium and Germany. 
Darwin gave us sound teaching when he compared man’s selective operations 
with those of Nature. Yet how many who are ready to expound Nature’s methods 
have been at the pains to see how man reaily proceeds? To the domesticated form 
our fashions are what environmental exigency is to the wild. For years the con- 
ventional Chinese primrose threw sporadic plants of the locse-growing stellata 
variety, promptly extirpated because repugnant to mid-Victorian primness. But 
when taste, as we say, revived, the graceful Star Primula was saved by 
Messrs. Sutton, and a stock raised which is now of the highest fashion. I dare 
assert that few botanists meeting P. stellata in Nature would hesitate to declare it 
a good species. This and the Shirleys precisely illustrate the procedure of the raiser 
of novelties. His operations start from a definite beginning. Asin the case of 
P. stellata, he may notice a mutational form thrown off perfect from the start, or, 
as in the Shirleys, what catches his attention may be the first indication of that 
! Marchant, Mém. Ac. roy. des sci. for 1719; 1721, p. 59, Pls. 6-7. I owe this 
reference to Coutagne, L’hérédité chez les vers a soie (Bull. sci. Fr. Belg., 1902). 
? This progress threatens to be rapid indeed. Since these lines were written 
Professor Hubrecht, in an admirable exposition (Pop. Sci. Monthly, July 1904) of 
De Vries’ Mutations-theorie, has even blamed me for having ten years ago attached 
any importance to continuous variation. Nevertheless, when the unit of segregation 
is small, something mistakably like continuous evolution must surely exist. (Cp. 
Johannsen, UVeb. Erbliehkeit in Poputationen und in reinen Linien, 1903.) 
1904. Pe 
