1872.] 319 [Cope. 
it mingles and breeds freely with both the others on the borders of their 
range. 
Third. That transitions from species to species in the present periods 
have not been observed ; nor have they been discovered in passing up- 
wards through strata of the earth’s crust. 
The all-sufficient answer to this statement is to be found in the imper- 
fection of our system of classification already pointed out. Thus, if we 
first assume with the anti-developmentalist, that varieties have a common 
parentage, and species distinct ones, when intermediate forms connecting 
so-called species are discovered, we must confess ourselves in error, and 
admit that the forms supposed to have had different origin, really had a 
common one. Such intermediate forms really establish the connection 
between species, but the question is begged at once by asserting unity of 
species, and therefore of origin, so soon as the intermediate form is found ; 
for, as before observed, it is not degree but constancy of distinction, which 
establishes the species of the zodlogical systems. Transitions between 
species are constantly discovered in existing animals : when numerous in 
individuals, the more diverse forms are regarded as ‘‘aberrant;”? when 
few, the extremes become “‘varieties,’’ and it is only necessary to destroy 
the annectant forms altogether, to leave two or more species. As the 
whole of a variable species generally has a wide geographical range, the 
varieties coinciding with sub-areas, the submergence or other change in 
the intervening surface would destroy connecting forms, and naturally 
produce isolated species. : 
Formerly, naturalists sometimes did this in their studies. A zodlogist 
known to fame, once pointed out to me some troublesome specimens 
which set his attempts at definition of certain species at defiance. ‘‘ These,’ 
said he, ‘“‘are the kind that I throw out of the window.’’ Naturalists 
having abandoned ‘‘throwing’”’ puzzling forms ‘‘out of the window,”’ 
the result of more honest study is a belief in evolution by four-fifths of 
them. 
Fourth. That the ‘‘variations’’ or intermediate types pointed to by 
evolutionists in favor of their positions, are exceptional, abnormal, or too 
few to be available in demonstration of the origin species in general, ete. 
The cases of transition, intermediate forms, or diversity in the brood, 
observed and cited by naturalists in proof of evolution, are few com- 
pared with the numbers of well defined, isolated species, genera, etc., 
though far more numerous than the author of the article criticised is aware 
of. Their value in evidence of the nature and origin of the permanent 
forms, is, it seems to me, conclusive, and to a certain extent, complete. 
By the inductive process of reasoning we arrive at a knowledge of the 
unknown from the known, a process which we act upon in our daily 
affairs, and one which constitutes the key to knowledge. It rests upon 
the invariability of nature’s operations under identical circumstances, and 
for its application merely demands that analysis and comparison shall fix 
that the nature of that of which something is unknown, is identical with 
