e great truths, from which all others are derived), he would compare
living forms, give them names to distinguish them, and other names to
connect them with each other. Taking his own body as the model with
which all living forms should be compared, and having measured them,
explained them thoroughly, and compared them in all their parts, he
would see that there is but small difference between the forms of living
beings; that by dissecting the ape he could arrive at the anatomy of
man, and that taking some other animal we find always the same ultimate
plan of organization, the same senses, the same viscera, the same bones,
the same flesh, the same movements of the fluids, the same play and
action of the solids; he would find all of them with a heart, veins,
arteries, in all the same organs of circulation, respiration, digestion,
nutrition, secretion; in all of them a solid frame, composed of pieces
put together in nearly the same manner; and he would find this system
always the same, from man to the ape, from the ape to the quadrupeds,
from the quadrupeds to the cetacea, birds, fishes, reptiles; this system
or plan then, I say, if firmly laid hold of and comprehended by the
human mind, is a true copy of nature; it is the simplest and most
general point of view from which we can consider her, and if we extend
our view, and go on from what lives to what vegetates, we may see this
plan--which originally did but vary almost imperceptibly--change its
scope and descend gradually from reptiles to insects, from insects to
worms, from worms to zoophytes, from zoophytes to plants, and yet
keeping ever the same fundamental unity in spite of differences of
detail, insomuch that nutrition, development, and reproduction remain
the common traits of all organic bodies; traits eternally essential and
divinely implanted; which time, far from effacing or destroying, does
but make plainer and plainer continually."

This is the writer who can see nothing in common between the horse and
the zebra except that each has a solid hoof.[114] He continues:--

"If from this grand tableau of resemblances, in which the living
universe presents itself to our eyes as though it were a single family,
we pass to a tableau rather of the differences between living forms, we
shall see that, with the exception of some of the greater species, such
as the elephant, rhinoceros, hippopotamus, tiger, lion, which must each
have their separate place, the other races