248 THE DOCTRINE OF DESCENT. 
XL 
The Pedigree of Vertebrate Animals. 
THE final result towards which the doctrine of Descent 
directs its efforts, is the pedigree of organisms, To 
work it out is to collect the almost inconceivable pro- 
fusion of facts accumulated in the course of about a 
century by descriptive botany and zoology, including 
comparative anatomy and the history of development, 
and to submit the existing special hypotheses to a minute 
scrutiny and renewed verification. We have therefore 
claimed in behalf of the doctrine of Derivation the 
privilege on which the progress of science generally 
relies—that of investigating according to determined 
points of view, and accepting probabilities as truth in 
the garb of scientific conjecture or hypothesis. It is 
manifest that when the doctrine of Descent first made 
its appearance with the arguments proposed by Darwin, 
it was only possible to indicate the most general outlines 
of this great pedigree, which it was the special task of 
the new direction of science to demonstrate in all its 
details. But however and wherever specific research 
was attempted, either the results contributed the form 
of some part of the great pedigree, or there was, from 
the first, reason to pre-suppose certain kinships, and the 
