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question which we are considering, for it is now certain that no one 
has succeeded, in spite of great efforts, in creating a persistent type, 
intermediate between the hare and the rabbit.”—(Blanchard. La Vie 
des Etres Animes. 1888, p. 231.) 
“Nothing of what has been said of the pretended half-breeds of 
the hare and the rabbit has been proved.”—(Flourens. p. log.) 
A similar difference of opinion is found in connection 
with the hybrid offspring of the dog and jackal. 
“ Experiments, carefully conducted in the Zoological Garden of 
the Agricultural Institute of the University of Halle, since the year 
1881, have proved that hybrids between the jackal and the domestic 
dog are capable of reproduction, not merely with individuals of pure 
blood, but among themselves.”—(Scientific News. Feb. 77, 1888, 
P- I57>) 
But this, again, is denied by M. Flourens, who bases 
his statement on actual experiment, conducted by himself. 
He asserts that the hybrid of the jackal and of the dog 
was as much a jackal as a dog ; but that when the hybrids 
bred with one another, there was less and less of the 
jackal until, in the fourth generation, the offspring alto 
gether resembled dogs.* 
It is quite conceivable that different experiments, possibly 
conducted under different conditions, may have different 
issues. But this discrepancy does not affect the argument, 
because we are quite prepared to find that species often 
resist modification, and we are not contending that all 
hybrid offspring are continuously fertile inter se, but that 
some are; and if the phenomenon only occurred now 
and then, it would afford a means of producing the trans 
mutation of species apart from Natural Selection. 
Another illustration of occasional birth variation is to 
be found in those cases in which an animal is born which 
differs from its parents sufficiently to constitute it a new 
Examen du Livre de M. Darwin, pp. no-111.