rms of adoration given to saints and the Virgin Mary in the Greek
and Roman churches historically imply a primitive Christianity on
which these newer beliefs and rites have been engrafted.

L.--SPECIES AND VARIETAL FORMS WITH REFERENCE TO THE UNITY OF
MAN.

In the concluding chapters of "Archaia" the nature of species, as
distinguished from varieties, was discussed, and specially applied to
the varieties and races of man. This discussion has been omitted from
the text of the present work; but, in an abridged form, is introduced
here, with especial reference to those more recent views of this
subject now prevalent in consequence of the growth of the philosophy
of evolution; but which I feel convinced must, with the progress of
science, return nearer to the opinions held by me in 1860, and
summarized below.

We can determine species only by the comparison of individuals. If all
these agree in all their characters except those appertaining to sex,
age, and other conditions of the individual merely, we say that they
belong to the same species. If all species were invariable to this
extent, there could be no practical difficulty, except that of
obtaining specimens for comparison. But in the case of very many
species there are minor differences, not sufficient to establish
specific diversity, but to suggest its possibility; and in such cases
there is often great liability to error. In cases of this kind we have
principally two criteria: first, the nature and amount of the
differences; secondly, their shading gradually into each other, or the
contrary. Under the first of these we inquire--Are they no greater in
amount than those which may be observed in individuals of the same
parentage? Are they no greater than those which occur in other species
of similar structure or habits? Do they occur in points known in
other species to be readily variable, or in points that usually remain
unchanged? Are none of them constant in the one supposed species, and
constantly absent in the other? Under the second we ask--Are the
individuals presenting these differences connected together by others
showing a series of gradations uniting the extremes by minute degrees
of difference? If we can answer these questions--or such of them as we
have the means of answering--in the affirmative, we have no hesitation
in referring all to the same species. If obliged to answer all or many
in the negative, we must at least hesitate in the identification