This physical man is an animal, amenable to the laws of animal growth. His body is the type of which theirs are imperfect copies. From two or three mineral substances his bones are crystalized, and articulated as the bones of all vertebrate animals, and over them the muscles are extended. From the _amphioxus_, too low in the scale of being to be called a fish; a being without organs, without a brain; little more than an elongated sack of gelatinous substance, through which a white line marks the position of the spinal cord and the future spinal axis; there is a slow and steady evolution to the perfected skeleton of man. His osseous structure is the type of all. The fin of the fish, the huge paddle of the whale, the cruel paw of the tiger, the hoof of the horse, the wing of the bird, and the wonderfully flexible hand of man, so exquisite in adaptations to be taken as an unqualified evidence of design, are all fashioned out of the same elementary bones, after one model. The change of form to meet the wants of their possessors, results from the relative enlargement or atrophy of one or more of these elements. When the fleshy envelope is stripped away, it is astonishing how alike these apparently divergent forms really are. In the whale the flesh unites the huge bones of the fingers and produces a broad, oar-like fin; in the tiger the nails become retractile talons; in the bird some of the fingers are atrophied, while others are elongated to support the feathers which are to offer resistance to the air in flight; in the horse the bones of the fingers are consolidated, and the united nails appear in the hoof. If there exists such perfect similarity in the bony structure of man to the animal world, the muscular system for which it furnishes support offers the same likeness. Trace any muscle in the human body from its origin to its termination, mark the points where it seizes the bones, the function it performs, and then dissect the most obscure or disreputable member of the vertebrate kingdom, and you will find the same muscle performing the same function. The talons of the tiger are extended and flexed by muscles, similar to those which give flexibility to the human hand, and the same elements are traceable in the ponderous paddle of the whale. More vital than the bony framework, or the muscles to which it gives support, is the nervous system, seemingly not only the central source of vital power, but the means of union and sympathetic relation of every cell and fiber of the entire body. The brain has been aptly compared to a central telegraphic office, and the nerves to the extended wires, which hold in communication and direct relation all the organs, and from which the functions of each are directed.