Thus, in all the great periods of the earth’s history of which we know anything, a part of the then living matter has had the form of polypes, competent to separate from the water of the sea the carbonate of lime necessary for their own skeletons.  Grain by grain, and particle by particle, they have built up vast masses of rock, the thickness of which is measured by hundreds of feet, and their area by thousands of square miles.  The slow oscillations of the crust of the earth, producing great changes in the distribution of land and water, have often obliged the living matter of the coral-builders to shift the locality of its operations; and, by variation and adaptation to these modifications of condition, its forms have as often changed.  The work it has done in the past is, for the most part, swept away, but fragments remain; and, if there were no other evidence, suffice to prove the general constancy of the operations of Nature in this world, through periods of almost inconceivable duration.

VII.

ON THE METHODS AND RESULTS OF ETHNOLOGY.

Ethonology is the science which determines the distinctive characters of the persistent modifications of mankind; which ascertains the distribution of those modifications in present and past times, and seeks to discover the causes, or conditions of existence, both of the modifications and of their distribution.  I say “persistent” modifications, because, unless incidentally, ethnology has nothing to do with chance and transitory peculiarities of human structure.  And I speak of “persistent modifications” or “stocks” rather than of “varieties,” or “races,” or “species,” because each of these last well-known terms implies, on the part of its employer, a preconceived opinion touching one of those problems, the solution of which is the ultimate object of the science; and in regard to which, therefore, ethnologists are especially bound to keep their minds open and their judgments freely balanced.

Ethnology, as thus defined, is a branch of anthropology, the great science which unravels the complexities of human structure; traces out the relations of man to other animals; studies all that is especially human in the mode in which man’s complex functions are performed; and searches after the conditions which have determined his presence in the world.  And anthropology is a section of zoology, which again is the animal half of biology—­the science of life and living things.

Such is the position of ethnology, such are the objects of the ethnologist.  The paths or methods, by following which he may hope to reach his goal, are diverse.  He may work at man from the point of view of the pure zoologist, and investigate the anatomical and physiological peculiarities of Negroes, Australians, or Mongolians, just as he would inquire into those of pointers, terriers, and turnspits,—­“persistent modifications” of man’s almost universal companion.  Or he may seek aid from researches into the most human manifestation of humanity—­language; and assuming that what is true of speech is true of the speaker—­a hypothesis as questionable in science as it is in ordinary life—­he may apply to mankind themselves the conclusions drawn from a searching analysis of their words and grammatical forms.