A multiplicity of protoplasts for a single species is a contradiction in terms. If two or more such individuals (or pairs), as like as the two Dromios, were the several protoplasts to several classes of organised beings (the present members being as like each other as their first ancestors were), the phænomenon would be the existence in Nature of more than one undistinguishable species, not the existence of more than one protoplast to a single species.
XXVIII.
A variety is a class of individuals, each belonging to the same species, but each differing from other individuals of the species in points wherein they agree amongst each other.
XXIX.
A race is a class of individuals concerning which there are doubts as to whether they constitute a separate species, or a variety of a recognised one. Hence, the term is subjective; i. e. it applies to the opinion of the investigator rather than to the object of the investigation; so that its power is that of the symbol for an unknown quantity in algebra. The present writer having, as yet, found no tribe or family, for which a sufficient reason for raising it to a new species has been adduced, has either not used the word race at all, or used it inadvertently. Its proper place is in investigation not in exposition.
XXX.
For an argument against the unity of the human species, drawn from the analogy of the lower animals, to be valid, it must be taken from a species co-extensive in its geographical distribution with man.
XXXI.
To be thus co-extensive, it must not only be spread over a large area, but it must be spread continuously.