etail of an animal's structure has been created for its benefit. On the
former hypothesis, for example, the teeth of the foetal 'Balaena' have
a meaning; on the latter, none. So far as we are aware, there is not
a phrase in the 'Origin of Species', inconsistent with Professor
Kolliker's position, that "varieties arise irrespectively of the notion
of purpose, or of utility, according to general laws of Nature, and may
be either useful, or hurtful, or indifferent."

On the contrary, Mr. Darwin writes (Summary of Chap. V.):--

"Our ignorance of the laws of variation is profound. Not in one case out
of a hundred can we pretend to assign any reason why this or that part
varies more or less from the same part in the parents...The external
conditions of life, as climate and food, etc., seem to have induced some
slight modifications. Habit, in producing constitutional differences,
and use, in strengthening, and disuse, in weakening and diminishing
organs, seem to have been more potent in their effects."

And finally, as if to prevent all possible misconception, Mr. Darwin
concludes his Chapter on Variation with these pregnant words:--

"Whatever the cause may be of each slight difference in the offspring
from their parents--and a cause for each must exist--it is the steady
accumulation, through natural selection of such differences, when
beneficial to the individual, that gives rise to all the more important
modifications of structure which the innumerable beings on the face of
the earth are enabled to struggle with each other, and the best adapted
to survive."

We have dwelt at length upon this subject, because of its great general
importance, and because we believe that Professor Kolliker's criticisms
on this head are based upon a misapprehension of Mr. Darwin's
views--substantially they appear to us to coincide with his own. The
other objections which Professor Kolliker enumerates and discusses are
the following*:--([Footnote] *Space will not allow us to give Professor
Kolliker's arguments in detail; our readers will find a full and
accurate version of them in the 'Reader' for August 13th and 20th,
1864.)

"1. No transitional forms between existing species are known; and
known varieties, whether selected or spontaneous, never go so far as to
establish new species."

To this Professor Kolliker appears to attach some weight. He makes the
suggestion that the short-faced tumbler pigeon may be a pathological
product.

"