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species, such as could be established by observation by 
experiment and from reasonable inference, would tend to 
confirm, if that were needed, a belief for which there was 
already the most abundant evidence. The argument from 
morphology, which is really based on the degradation of 
an organ or an organism, looked at either from a structural 
or from a functional point of view, could only go to show 
that all change was not necessarily progressive change 
according to a particular conception of progress ; but it 
would have no power to alter the established belief that 
the process of progressive Organic Evolution must have 
taken place, and if it were not always possible to give 
actual illustrations of this process, the believer in Organic 
Evolution would come to the conclusion that the limitation 
of his knowledge, and not the weakness of his arguments, 
was to blame. He would still be bound to believe in the 
progressive development of organs and of organisms, and 
there would be nothing inconsistent with his belief in the 
fact that perfect organs could be further modified and even 
degraded. Consequently, in his view, some imperfect 
organs would be on the upward grade, albeit others could 
be proved to be on the downward grade. Many imperfect 
organs would still remain as illustrations of that gradual 
progressive evolution which, he has good reason to believe, 
must have taken place. 
Mais nous avons changé tout cela. The theory of 
Natural Selection has largely modified the view of im 
perfect organs just referred to. There is a passage in 
Mr. Wallace’s writings which brings out this point in a 
very distinct manner. In 1855 he wrote an Essay, in 
which he explained the significancy of imperfect organs 
from the point of view of a belief in Organic Evolution :— 
“To every thoughtful naturalist the question must arise: What 
are rudimentary organs for? What have they to do with the great