when we reach the tertiary, we find the shell animals approaching
nearer,^ in specific forms, to existing species, than those of previous
formations; and along with these are skeletons of birds and mammalia,
including quadrupeds and quadrumana. The geological
epoch of man has yet to be determined: it is certain that the investigations
of each succeeding year tend to throw it further back in
time I nor are there wanting good authorities who would not be
surprised to find his remains in the tertiary, where the quadrumana
have been recently, and for the first time, discovered.
A discussion of such difficulty and magnitude as the' theoiy of
progressive development, would be out of place here; but this idea
seems to have taken possession of many of our leading authorities.
or, at first sight, would it seem that the long-mooted question of
the ongin of species could properly find a place in an essay on
Medical Climate; yet all these subjects have points of contact, which
render it difficult to isolate them. Our object being to study the
influence of climates and their diseases on races, we assuredly, d
prion, should expect species and mere varieties to be influenced’in
different degrees. Natural histoiy teaches us that the white and
black races, for example, are distinct species. We should, therefore,
regard their origin as independent of climate; and if we can show
that these races are. not affected in like manner by diseases, we fortify
the conclusion to which natural history has led us. 'Well-ascertained
varieties of a given species, however widely scattered, may exchange
habitations with comparative impunity; while, on the contrary, as a
general rule, each species of a genus has its prescribed geographical
range. The species, for example, of the reindeer and the white bear,
in the Arctic, can no more exchange places with the deer and bear
of the Tropics, than can the Esquimau with the tropical Negro.
Such facts as these, then, clearly show how deeply our subject
implicates the investigation of species and varieties.
A great diversity of opinion has existed with regard to the origin
of .species, but we shall allude only to two of the more prominent.
Of the first school, Cuvier may be regarded as the most distinguished
authority. He contends that the geological history of the earth
should be divided into distinct periods, each of which is complete in
itself; that there has been, since the dawn of life, a succession of
distinct creations and destructions; and that the organized beings of
one epoch have no direct connection, by way of descent, with those
of the preceding. According to this theory, the species of animals
and plants now scattered over the face of the earth are primordial
forms, the result of a special creation; which have endured without
materiai change to the present, and which will endure unchanged
until their allotted term of existence has expired.
The opposing school may be represented by Geoffroy St. Hilaire
the contemporary of Cuvier. It is contended by his followers thal
there has been but one creation, and no cessation of life, since the
first organized beings were brought into existence; that, by a law
of progressive development or evolution, in accordance with new
chmatie influences, brought into action, from time to time by
changes in the physical condition of the globe, the living beings of
one period have given ongin to those which follow; and so on
through the whole chain, from the earliest and simplest forms to the
last and most complex. Moreover, that what we term species remains
permanent as long as the physical conditions which produced them
remain unchanged. Some of this school go so far as to assert that
no such tiling as “ species” exists; that Nature creates only individu
a ls,^ two animals or plants being exactly alike, and the species
of each genus running together so closely as to leave their boundaries
difficult, and often impossible, to define. They forther contend
at transformations of species are incessantly going on around us’
H H ® y as not to be easily recognized, in the atom of time
which has been consumed so far by the human family.
Those who contend that all the races of men are of common
origin, must, m spite of themselves, fall into these heterodox opinions
of Lamarck, Oken, and St. Hilaire; because the races of men differ
quite as much, anatomically and physiologically, as do the species
of other genera m the animal kingdom - the Equid®, the Ursines,
Felines, &c Professor Owen himself cannot point out greater
ifferences between the lion, tiger, and panther, or the dog, fox,
Mongol1 Ja than those between the White Man, Negro, and
According to the above doctrine, not only are the individuals of
our present Fauna and Flora direct descendants of the fossil world
but they are probably destined to be the ancestry of others still
more perfect. The climatic influences now at work, it is supposed,
be changed, and development take up its line of march and carry
on the great plan of the Creator. Thus, man himself is to be the
progenitor of beings far more perfect than himself; and it must be
n essed that there is no small room for improvement. But there
is no good reason why we should enter the lists with these disputants,
as the two schools unite at a point which meets all the requisitions
of our present investigation. The term species is, at best,
M co™ tl(\nal. one> without a fixed definition; and is used by
parties t0 designate certain groups of forms closely resembling