PROOFS DEMANDED BUT NEEDLESS. 359 
mammals, and thus continually further back to lower stages 
of the vertebrata down to their lowest invertebrate roots, 
nay, even down to a simple plastid—as a general theory. 
On the other hand, the special tracing of the human 
pedigree, the closer definition of the animal forms known 
to us, which either actually belong to the ancestors of man, 
or at least stand in very close blood relationship to them, 
will always remain a more or less approximate hypothesis 
of descent, all the more in danger of deviating from the real 
pedigree the nearer it endeavours to approach it by search- 
‘ing for the individual ancestral forms. This state of things 
results from the immense gaps in our paleontological know- 
ledge, which can, under no circumstances, ever attain to 
even an approximate completeness. 
A thoughtful consideration of this important circumstance 
at once furnishes the answer to a question which is 
commonly raised in discussing this subject, namely, the 
question of scientific proofs for the animal origin of the 
human race. Not only the opponents of the Theory of 
Descent, but even many of its adherents who are wanting 
in the requisite philosophical culture, look too much for 
“signs” and for special empirical advances in the science of 
nature. They await the sudden discovery of a human race 
with tails, or of a talking species of ape, or of other living 
or fossil transition forms between man and the ape, which 
shall fill the already narrow chasm between the two, and 
thus empirically “prove” the derivation of man from apes. 
Such special manifestations, were they ever so convincing 
and conclusive, would not furnish the proof desired. Un- 
thinking persons, or those unacquainted with the series of 
biological phenomena, would still be able to maintain the 
