they call by this name, without perceiving, that, though they bring them together and describe them according to other characters, they have been unconsciously led to unite them from the general similarity of their port and bearing.  Take, for instance, the families of Pines, Oaks, Beeches, Maples, etc., and you feel at once, that, besides the common characters given in the technical descriptions of these trees, there is also a general resemblance among them that would naturally lead us to associate them together, even if we knew nothing of the other features of their structure.  By an instinctive recognition of this family likeness between plants, botanists have been led to seek for structural characters on which to unite them, and the groups so founded generally correspond with the combinations suggested by their appearance.

By a like process Lamarck combined animals into families.  His method was adopted by French naturalists generally, and found favor especially with Cuvier, who was particularly successful in limiting families among animals, and in naming them happily, generally selecting names expressive of the features on which the groups were founded, or borrowing them from familiar animals.  Much, indeed, depends upon the pleasant sound and the significance of a name; for an idea reaches the mind more easily when well expressed, and Cuvier’s names were both simple and significant.  His descriptions are also remarkable for their graphic precision,—­giving all that is essential, omitting all that is merely accessory.  He has given us the key-note to his progress in his own expressive language:—­

“Je dus donc, et cette obligation me prit un temps considerable, je dus faire marcher de front l’anatomie et la zoologie, les dissections et le classement; chercher dans mes premieres remarques sur l’organisation des distributions meilleures; m’en servir pour arriver a des remarques nouvelles; employer encore ces remarques a perfectionner les distributions; faire sortir enfin de cette fecondation mutuelle des deux sciences, l’une par l’autre, un systeme zoologique propre a servir d’introducteur et de guide dans le champ de l’anatomie, et un corps de doctrine anatomique propre a servir de developpement et d’explication au systeme zoologique.”

It is deeply to be lamented that so many naturalists have entirely overlooked this significant advice of Cuvier’s, to combine zooelogical and anatomical studies in order to arrive at a clearer perception of the true affinities among animals.  To sum it up in one word, he tells us that the secret of his method is “comparison,”—­ever comparing and comparing throughout the enormous range of his knowledge of the organization of animals, and founding upon the differences as well as the similarities those broad generalizations under which he has included all animal structures.  And this method, so prolific in his hands, has also a lesson for us all.  In this country there is a growing interest in the study of Nature; but while there exist hundreds of elementary works illustrating the native animals of Europe, there are few such books here to satisfy the demand for information respecting the animals of our land and water.  We are thus forced to turn more and more to our own investigations and less to authority; and the true method of obtaining independent knowledge is this very method of Cuvier’s,—­comparison.