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the zoological or botanical distance between species, as the latter maintains 
the physical distance between the heavenly bodies. All these have their 
perturbations, their unexplained phenomena. Do we on account of these 
doubt the great laws which hold in their place the smallest of the satellites 
as well as the largest of the suns ? By no means. Can we on similar 
grounds deny the fact which secures the separation of the species nearest to 
each other as well as of the most distant groups ? No more than in the 
previous case. In astronomy we should discard at once every hypothesis in 
opposition to the first, and although the complication of phenomena is much 
greater in botany and in zoology, a serious consideration of the subject will 
always lead to the rejection of every doctrine that is discordant with the second. 
“ Human art may produce results which seem at first not to yield to rules 
of hybridation. It has done so once, and may do so again. For all that, it 
has not changed the natural and general law, nor has it demonstrated that 
it is non-existent." — Quatrefage’s Etude sur le Transformisme, Paris, 1870. 
The same observations apply to past geological ages as well 
as to the present. All things being alike in other respects, 
fossil species are as well defined and as distinct as those of 
the present era. 
Everything leads us to the conclusion that the laws of the 
organic world have not changed since the beginning. To 
admit the contrary is to oppose to all that we know concern- 
ing the present and the past of our globe, the possible, the 
unknown; or, in other words, hypothesis, having for its foun- 
dation our very ignorance. f 
The study of Dr. Thomson’s Address has unexpectedly 
revealed to me the weakness of the case of the Evolutionists in 
this, which I had supposed to be their chosen battle-ground — 
the more so as I find, from the President’s own admission, 
that the recently deceased Von Baer refused to give his assent 
to the doctrines of evolution. 
“ Although Von Baer’s researches, according to the light in 
which we may now view them, contributed in no small degree 
to the introduction of the newer views of the morphological 
relations of organic structure which have culminated in the 
theory of descent, yet he was unwilling to adopt the views of 
Darwin, and one of his latest writings, completed in the last 
year of his life, was in vigorous opposition to that doctrine.” 
So far, I quote from Dr. Thomson. I now turn for further 
information to a paper by G. Moquin-Tandon, “ Do quelques 
Applications de l’Embryologie a la Classification methodique 
des Animaux.”* This able writer traces out the “Idee mere 
* Annalcs dot Sciences Naturcllcs; Zoolocjie, 1S74-5. 
f See Appendix F, 
