Craniology is not anthropology; it assists it materially, but the partial results which it obtains have not necessarily the same value in the more general point of view of anthropology. Every classification, based on the form of the skull, will be necessarily an artificial classification, because it will only rest upon one sole order of phenomena. Besides, this study presents great difficulties from the individual differences which the various heads show, in which the qualities belonging to the individual have been so far able to hide the general characters of the race, that these often remain unrecognisable. Divisions have also increased in proportion as craniological collections have come richer in specimens. Morton only reckoned eleven human races, but he believed under the truth. We may very well have a poor idea of the value of this classification by studying the materials which were used by the philosopher of Philadelphia. Besides the American race, Morton had only a very few skulls at his disposal. The Philadelphian collection, which has been much increased since his death, contained, only a few years ago, 1035 skulls, 38 of them pathological; there remain therefore but 997. Out of this number the American race figures in 502, or more than one-half. There remains, therefore 495, 154 of which came from the valley of the Nile; so that merely 350 skulls represent the whole of Europe, Asia, the Oceanic countries, and Africa (excepting Egypt). This is not much for the purpose of classing a population likely to be raised to five hundred millions of inhabitants.[336] It remains for us to study and determine the intrinsic value of each of these heads. The authentic production of a skull is not always easy to be established when it comes from the other side of the world, obtained by travellers who have not made a special study of anthropology; it is even less so when a skull is dug up in a burial ground, where there may be a certain promiscuousness very apt to hinder our inquiries. Errors of this kind steal into science only too often, and we have for a long time in particular objected to the name of _Gallic mummy_, which has been given to a body in a collection at Paris, the history of which does not at all justify this denomination, since we simply believe that _when it was first dug up_ it was only referred back to the _thirteenth_ century![337]