alities where they could exist, and by
the variety of seasons--_i.e._, by the influences of different
atmospheric conditions--the time during which they could maintain
their existence.

"By means of these wise precautions of nature everything is well
balanced and in order. Individuals multiply, propagate, and die in
different ways. No species predominates up to the point of effecting
the extinction of another, except, perhaps, in the highest classes,
where the multiplication of the individuals is slow and difficult;
and as the result of this state of things we conceive that in
general species are preserved" (p. 22).

Here we have in anticipation the doctrine of Malthus, which, as will be
remembered, so much impressed Charles Darwin, and led him in part to
work out his principle of natural selection.

The author then taking up other subjects, first asserts that among the
changes that animals and plants unceasingly bring about by their
production and _debris_, it is not the largest and most perfect animals
which have caused the most considerable changes, but rather the coral
polyps, etc.[165] He then, after dilating on the value of the study of
the invertebrate animals, proceeds to define them, and closes his
lecture by describing the seven classes into which he divides this
group.

II. _Recherches sur l'Organisation des Corps vivans, 1802 (Opening
Discourse)._

The following is an abstract with translations of the most important
passages relating to evolution:

That the portion of the animal kingdom treated in these lectures
comprises more species than all the other groups taken together is,
however, the least of those considerations which should interest my
hearers.

"It is the group containing the most curious forms, the richest in
marvels of every kind, the most astonishing, especially from the
singular facts of organization that they present, though it is that
hitherto the least considered under these grand points of view.

"How much better than learning the names and characters of all the
species is it to learn of the origin, relation, and mode of
existence of all the natural productions with which we are
surrounded.

"_First Part: Progress in structure of living beings in proportion
as circumstances favor them._

"When we give continued attention to the examination of the
organization of different living beings, to that of different
systems which this