THE 
JOURNAL OF SCIENCE. 
APRIL, 1884. 
I. HYBRIDISM WITH REFERENCE TO THE 
THEORY OF EVOLUTION. 
By J. W. Slater. 
S ^HE rarity, or rather, in the opinion of some persons, 
^ the absolute non-existence of true hybrids capable of 
reproduction, is sometimes yet brought forward as a 
faCt hostile to the doCtrine of Development. Even avowed 
Evolutionists occasionally make such statements as the 
following, which we have recently met with in a book of 
much merit : — “ The objection drawn from the physiological 
difference between species and races still exists unrefuted,” 
and is indeed “the great stumbling-block to all theories of 
Evolution.” 
It will therefore not be an idle undertaking to re-examine 
the faCts bearing on this question, and see whether they 
necessitate or admit of the interpretation so often put upon 
them. 
Briefly recapitulating the views of the Old School we find 
it asserting that whilst orders, families, and genera are 
mere man-made groups, having no aCtual existence, species 
possess, on the contrary, a distinct objective character. 
Each such species consists of animals — or plants — which 
are, or might have been, descended from one original couple, 
and it is distinguished from every other species morphologic- 
ally and physiologically. The morphological characteristic 
was a structural resemblance between the individuals of one 
and the same species, coupled with a structural dissimilarity 
VOL. VI. (THIRD SERIES.) O 
