called into play, and may be fairly taken to account for many of the phenomena of Nature
I t seems also that, so far from there being a constant tendency in Nature to preserve
t h e most divergent offspring of any one species, and thus form new species, and isolate
t h e extremities by extinction of intermediate links, i t is precisely these connecting links
which in the struggle for existence should survive; for they, being neither the one thing
nor t h e other, can adapt themselves to either condition, and any cause which might tend
to exterminate one or the other extreme would not affect to the same extent the intermediate
varieties; and they, under t h e complex system of laws, in ever varying conditions of
life would remain in a perpetual state of fluctuation between the extremes, and hi all cases
be t h e survivors, an anomalous mixed race being t h e result.
I t is by t h e introduction of new blood that the greatest energy of variation is produced;
and t h e unmistakable and immediate effects which we perceive to arise from it in a state of
domestication ought, if the cases were parallel, to enable us to detect it at once if it were
to occur in a wild species; but, notwithstanding the close watch k e p t over Nature in these
days, no approach to it is discovered; and the natural inference to be drawn is, t h a t in a state
of nature interbreeding of species does not take place.
To sum up in a few words t h e drift of t h e preceding paragraphs will show the chief points
on which the laws of modified descent, if true, are as yet obscure.
I. The law of generation does not account for the origin of life.
I I . Animal and vegetable life, though as closely approximating in outward form as
the internal divisions of either kingdom, are almost conclusively shown by Geology to
have started independently.
I I I . The various orders of t h e animal and vegetable kingdoms seem to have appeared
too suddenly on t h e stage.
IV. The absence of any proof of a general tendency in each era to approximate to
the incoming forms.
V. The animal and vegetable kingdoms appear to have progressed in parallel lines
with no tendency to divergence.,
V I . The oldest stratum known to contain fossils a t all contains them in great variety.
V I I . The varieties or " artificial species" produced under domestication have not
become permanently settled in possession of their specific diagnoses.
V I I I . The unsatisfactory nature of many of the explanations of natural phenomena,
on t h e hypothesis of modified descent.
IX. The marked difference between the broods of a wild species and a domestic
species, in t h e similarity outwardly of all t h e individuals.
X. That an evolution theory requires the power of variation to be unlimited, whereas
all experiments tend t o show that i t has a limit.
The above considerations point to t h e existence in nature of causes acting in concert with
t h e laws of generation, and which require t o be known before t h e results can with any certainty
be predicted. The laws governing the animated portion of the globe are doubtless as
definite and fixed as those that govern the motions of t h e great spheres of t h e universe; but
it must be remembered that an astronomical calculation, based accurately on the known
laws, gives a result very wide of the truth, unless the various disturbing influences, as
refraction, parallax, precession, nutation, and all t h e numerous sources of error are accurately
judged and allowed for. In like manner, if we really knew the nature and value of the
disturbing influences acting in concert with the law of generation, we should be able to
calculate with equal accuracy t h e problems presented in t h e phenomena of life.
These remarks are made in no carping spirit, b u t in t h e conviction that an evolution theory
is not alone sufficient to fulfil the conditions of the case, t h a t the limit to which evolution
exists and the causes of limitation are unknown. If it be the correct solution to the enigma
—if it be the t r u t h — t h e pointing out of difficulties can do no damage to its cause: it may
stimulate discussion and inquiry ; but light and t r u t h go hand i n hand. The t r u t h is l i k e a
mighty torrent—now in view, now lost to sight in deep gorges—that only flows on with
more resistless force for the obstruction of a temporary barrier, and, ever expanding, ever
increasing in power, loses itself at last in eternity. Magna est Veritas et prcevalebit.
But further, if the capability of variation in direct descent be so wide and so universally
in action as the theory of modified descent requires us to believe, classification on a natural
system is simply impossible with regard to t i m e ; for we know not, and can never hope to
know to any appreciable extent, the lineage of even a single genus, the blanks in the
geologic record preventing the recognition of progenitors i n their altered posterity; and as
regards space, to which indeed almost all classification is limited, any system of arrangement
based on actual affinity is equally hopeless; for the degree of relationship by no means
varies as the similarity either in form, habit, or structure; and if the lineage be unknown
the former cannot be determined with certainty by the latter. If it could be so determined,
of course a close study of the structure and habits of any particular individual would fix
positively its nearest relations and exact place in the " schema naturae." Among individuals
of a species it often happens that the most nearly related exhibit wide differences, while the
distantly related show strange resemblances, which would entirely mislead a classifier
unacquainted with their origin and descent; and if we assume that different species as well
as different individuals may be descended from a common stock, we must also take for
granted that the same phenomena will occur; and in this case there will be wide differences
between closely related species, and great similarity sometimes displayed between those
whose connexion is more remote. In short, resemblances in structure and habit do not
vary directly as the amount of consanguinity, and, though of great value in any classification,
they do not suffice alone to fix the position of a species or genus according to a
natural theory.
Let us imagine for a moment a philosopher from another world attempting to classify the
different varieties of the human race, which most people agree in considering to be descended
from a single original stock; and though he would probably easily define the broad lines of
division, when he reached the smaller groups, the difficulties that he would encounter
become evident in the aberrant nature of the variations in individual size, shape, and colour,
so general among mixed races.
Cases of somewhat analogous arrangements among birds will occur to the mind of every
ornithologist; and a few minutes' reflection will convince the reader that to subdivide a
b 2