PRESIDENT’S ADDRESS. 15 
the original parents. Many of these can be bred true, and if found 
wild would certainly be described as good species. Confronted by the 
difficulty I have put before you, and contemplating such amazing poly- 
morphism in the second generation from a cross in Antirrhinuwm, Lotsy 
has lately with great courage suggested to us that all variation may be 
due to such crossing. I do not disguise my sympathy with this effort. 
After the blind complacency of conventional evolutionists it is refresh- 
ing to meet so frank an acknowledgment of the hardness of the problem. 
Lotsy’s utterance will at least do something to expose the artificiality of 
systematic zoology and botany. Whatever might or might not be 
revealed by experimental breeding, it is certain that without such tests 
we are merely guessing when we profess to distinguish specific limits 
and to declare that this is a species and that a variety. The only defin- 
able unit in classification is the homozygous form which breeds true. 
When we presume to say that such and such differences are trivial and 
such others valid, we are commonly embarking on a course for which 
there. is no physiological warrant. Who could have foreseen that the 
Apple and the Pear—so like each other that their botanical differences 
are evasive—could not be crossed together, though species of Antir- 
rhinum so totally unlike each other as majus and molle can be 
hybridized, as Baur has shown, without a sign of impaired fertility? 
Jordan was perfectly right. The true-breeding forms which he dis- 
tinguished in such multitudes are real entities, though the great 
systematists, dispensing with such laborious analysis, have pooled them 
into arbitrary Linnean species, for the convenience of collectors and for 
the simplification of catalogues. Such pragmatical considerations may 
mean much in the museum, but with them the student of the physio- 
logy of variation has nothing to do. These ‘little species,’ finely cut, 
true-breeding, and innumerable mongrels between them, are what he 
finds when he examines any so-called variable type. On analysis the 
semblance of variability disappears, and the illusion is shown to be due 
to segregation and recombination of series of factors on pre-determined 
lines. As soon as the ‘ little species ’ are separated out they are found 
to be fixed. In face of such a result we may well ask with Lotsy, 
is there such a thing as spontaneous variation anywhere? His answer 
is that there is not. 
Abandoning the attempt to show that positive factors can be added 
to the original stock, we have further to confess that we cannot 
often actually prove variation by loss of factor to be a real pheno- 
menon. Lotsy doubts whether even this phenomenon occurs. The 
sole source of variation, in his view, is crossing. But here I 
think he is on unsafe ground. When a well-established variety like 
‘Crimson King’ Primula, bred by Messrs. Sutton in thousands of 
individuals, gives off, as it did a few years since, a salmon-coloured 
