apes, is extremely close.
EMBRYONIC DEVELOPMENT.
[Fig. 1. Shows a human embryo, from Ecker, and a dog embryo, from
Bischoff. Labelled in each are:
a. Fore-brain, cerebral hemispheres, etc. b. Mid-brain, corpora
quadrigemina. c. Hind-brain, cerebellum, medulla oblongata. d. Eye. e.
Ear. f. First visceral arch. g. Second visceral arch. H. Vertebral
columns and muscles in process of development. i. Anterior extremities.
K. Posterior extremities. L. Tail or os coccyx.]
Man is developed from an ovule, about the 125th of an inch in diameter,
which differs in no respect from the ovules of other animals. The
embryo itself at a very early period can hardly be distinguished from
that of other members of the vertebrate kingdom. At this period the
arteries run in arch-like branches, as if to carry the blood to
branchiae which are not present in the higher Vertebrata, though the
slits on the sides of the neck still remain (see f, g, fig. 1), marking
their former position. At a somewhat later period, when the extremities
are developed, the feet of lizards and mammals, as the illustrious
Von Baer remarks, the wings and feet of birds, no less than the hands
and feet of man, all arise from the same fundamental form. It is, says
Prof. Huxley (14. Man s Place in Nature, 1863, p. 67.), quite in the
later stages of development that the young human being presents marked
differences from the young ape, while the latter departs as much from
the dog in its developments, as the man does. Startling as this last
assertion may appear to be, it is demonstrably true.
As some of my readers may never have seen a drawing of an embryo, I
have given one of man and another of a dog, at about the same early
stage of development, carefully copied from two works of undoubted
accuracy. (15. The human embryo (upper fig.) is from Ecker, Icones
Phys., 1851-1859, tab. xxx. fig. 2. This embryo was ten lines in
length, so that the drawing is much magnified. The embryo of the dog is
from Bischoff, Entwicklungsgeschichte des Hunde-Eies, 1845, tab. xi.
fig. 42B. This drawing is five times magnified, the embryo being
twenty-five days old. The internal viscera have been omitted, and the
uterine appendages in both drawings removed. I was directed to these
17