as modifying the individual organism, and thus
supplying the basis for the operation of natural selection. Haeckel also
became an advocate of this idea, and presently there arose a so-called
school of neo-Lamarckians, which developed particular strength and
prominence in America under the leadership of Professors A. Hyatt and E.
D. Cope.

But just as the tide of opinion was turning strongly in this direction,
an utterly unexpected obstacle appeared in the form of the theory of
Professor August Weismann, put forward in 1883, which antagonized the
Lamarckian conception (though not touching the Darwinian, of which
Weismann is a firm upholder) by denying that individual variations,
however acquired by the mature organism, are transmissible. The
flurry which this denial created has not yet altogether subsided, but
subsequent observations seem to show that it was quite disproportionate
to the real merits of the case. Notwithstanding Professor Weismann's
objections, the balance of evidence appears to favor the view that the
Lamarckian factor of acquired variations stands as the complement of the
Darwinian factor of natural selection in effecting the transmutation of
species.

Even though this partial explanation of what Professor Cope calls the
"origin of the fittest" be accepted, there still remains one great life
problem which the doctrine of evolution does not touch. The origin
of species, genera, orders, and classes of beings through endless
transmutations is in a sense explained; but what of the first term of
this long series? Whence came that primordial organism whose transmuted
descendants make up the existing faunas and floras of the globe?

There was a time, soon after the doctrine of evolution gained a hearing,
when the answer to that question seemed to some scientists of authority
to have been given by experiment. Recurring to a former belief, and
repeating some earlier experiments, the director of the Museum of
Natural History at Rouen, M. F. A. Pouchet, reached the conclusion that
organic beings are spontaneously generated about us constantly, in the
familiar processes of putrefaction, which were known to be due to the
agency of microscopic bacteria. But in 1862 Louis Pasteur proved that
this seeming spontaneous generation is in reality due to the existence
of germs in the air. Notwithstanding the conclusiveness of these
experiments, the claims of Pouchet were revived in England ten years
later by Professor Ba