REVIEWS—ON THE ORIGIN OF SPECIES. 403 
the ruminant from an animal furnished with cutting teeth in its upper 
jaw. We have already referred to this st:bject, and we need only say now 
that the facts can be generalised in at least two distinct ways, the one 
followed by Darwin, in which imperfectly developed organs are regarded 
as indicating their partial suppressions by accidental variety, and the 
view previously taken that in forming a perfect creation in which every 
position*should be suitably filled, and the greatest possible amount: of 
life and enjoyment be produced ; the almighty and all-wise intelligence 
used a plan, according to which the required variety depended not on 
so many altogether different types of structure, but on changes in the 
comparative development of parts in structures belonging to one type, 
the common relationship giving unity to the whole, and harmonising 
the various parts into one grand system. According to this view cer- 
tain elements of structure belonging to one organic type would receive 
their fullest development in one form, and in others would be gradually 
reduced until they existed only imperfectly or rudimentally, so as in 
many instances not to be observable without investigation or only to 
become observable under peculiar circumstances. We account the 
latter view the most antecedently probable because it best explains 
the analogies as well as affinities observable in nature ; because it is 
most consistent with the uniformity and completeness of the design 
which seems to us to pervade creation, and is more readily conceived 
as the result of ordinary intelligence. But it would be enough, as an 
answer to Prof. Huxley’s argument, merely to shew that there is a 
way of viewing the occurrence of imperfectly developed organs, which . 
is reasonable and consistent in itself, and by no means requires or 
favours the Darwinian hypothesis. 
On the whole, it must be acknowledged that the cases of the phe- 
nomena exhibited by species, suggested by Darwin, have a real exis- 
tence in Nature. Proceeding to the second test, we deny that they 
are, so far as we yet know, competent to give rise to all the phe- 
nomena; since, besides the admitted difficulty about sterility of hy- 
brids, it has not been proved that the tendency to variation ever passes 
the boundaries imposed by predominating developmental tendencies 
which constitute species, and it is not proved that any degrees of varia- 
tion entitled to be called specific have arisen within our knowledge, or 
that time, however long the period attained, tends to increase the extent 
of variation. We cannot affirm that the contradictory of these proposi- 
tions is absolutely proved, but it seems to us in each case to be more 
