The Theory of Evolution 47 
be supposed to have taken place. Fleischmann points out 
that these facts were supposed to be in full harmony with 
the theory of descent. 
The analysis of the origin of the foot of the horse gave 
even better evidence, it was claimed, in favor of the theory. 
The foot consists of a single series of bones corresponding 
to the middle finger and toe. When, as sometimes happens, 
individual horses are found in which in addition to the single 
middle finger two smaller lateral fingers with small hoofs 
appear, the followers of the descent theory rejoiced to be able 
to bring this forward as a confirmation of their doctrine. 
The occurrence was explained as a sporadic return to an 
ancestral form. The naive exposition of the laws of in- 
heritance that were supposed to control such phenomena 
was accepted without question. And when finally a large 
number of fossil remains were found by paleontologists, — 
remains showing a gradual increase in the middle finger, 
and a decrease in size of the lateral fingers, — it was sup- 
posed that the proof was complete; and anatomists even 
went so far as to hold that the original ancestor of the 
horse was a five-fingered animal. 
This same law of type of structure was found to extend to 
the entire vertebrate series, and the only plausible explana- 
tion appeared to be that adopted by Darwin and his fol- 
lowers, namely, that the resemblance is the result of the 
blood-relationship of the different forms. But a simple com- 
parison of the skeleton of the limbs if carried out without 
theoretical prejudice would show, Fleischmann thinks, that 
there is only a common style, or plan of structure, for the 
vertebrates. This anatomical result has about the same 
value as the knowledge of the different styles of historical 
architecture — that, for instance, all large churches of the 
Gothic period have certain general principles in common. 
The believers.in the theory of descent have, however, he 
thinks, gone beyond the facts, and have concluded that the 
