THE EXPERIMENTAL STUDY OF GENETIC RELATIONSHIPS 1 33 
founder of the Linnaean Society, wrote in 1807, "By species are 
understood so many individuals, or, among the generahty of animals, 
so many pairs, as are presumed to have been formed at the creation, 
and have been perpetuated ever since ; for though some animals appear 
to have been exterminated, we have no reason to suspect any new 
species has been produced ; neither have we any cause to suppose any 
species of plant has been lost, or any new one permanently established, 
since their first formation, notwithstanding the speculations of some 
philosophers." 
Although Linnaeus had reached the remarkable conclusion that 
species were, in some way, genetically interrelated, the second edition 
of the "Species Plantarum" and the inaugural dissertation of his 
pupil, Hartmann, contain so many preposterous guesses as to the 
parentage of certain supposed hybrid species, that he could certainly 
have had no conception of the limits of hybridization, or of the segre- 
gation which so often follows it. Obviously, he supposed that species 
originated as stable first generation hybrids — not a surprising theory, 
considering that, in his experiments with Tragopogon, he had chanced 
upon the one family in which parthenogenesis is so common that 
hybrids are often constant from generation to generation. 
Linnaeus, knowing nothing about the geological history of organ- 
isms, had to construct a scheme of evolution which involved only the 
Mosaic "days of creation" and the few thousand years of recorded 
history. Having assumed the hybrid origin of species, it was clearly 
necessary for him to hypothecate the creation in the beginning of a 
considerable number of distinct forms representing the natural orders, 
for otherwise there could have been no material for hybridization to 
work upon. Moreover, since these originally created forms were so 
different that one could hardly believe in their crossing, he invoked 
miraculous intervention to account for it. Finally, in order to preserve 
intact the limits of the orders, he seems to have implied that the more 
fundamental characters were transmitted by the mother; the super- 
ficial ones by the father. His philosophical difficulties and the way he 
got around them now seem very amusing; but, as we shall see later, 
the same difficulties still confront certain modern geneticists, who have 
either not been able to circumvent them at all or are beginning to 
whisper a hypothesis more fantastic than that of Linnaeus. 
Although Sir James Edward Smith's views were those which pre- 
vailed, for the most part, until the time of Darwin, there were occasional 
