Fig. 36.—Embryos of Four Mammals.
Dog, Bat, Rabbit, Man—at Three Different Stages of Development.
Comparative anatomy traces the arms and legs of man through various land forms back to the limbs of fishes. And the human heart and lungs, the liver, kidneys and stomach, the eyes and ears, the nose and mouth, have been fashioned from the organs of primitive creatures through successive modifications during countless ages. The larynx, which makes possible the human voice, appears in diverse stages of development in the Amphibia.
Man’s remote ape-like progenitors had tails, and for a time in its embryonic development, the human babe has a tail longer than his legs ([Fig. 36, middle row]). Moreover, in the annals of medical science, there are records of many otherwise well-formed children born with tails. Professor Haeckel, in his “Evolution of Man,” shows photographs of a six-months-old tailed boy ([Fig. 37]). The presence of this tail is another rare instance of the vaulting power of heredity—a case in which Nature recalls a phase of her distant life.
Fig. 37.—Tail of a Six-Months-old Boy.
Removed by Operation by Dr. Granville Harrison, in 1901. “A great number of such cases,” says Haeckel, “are given by Max Bartells in his essay on ‘Tailed Men,’ 1884.”
Every human being carries the rudiment of an ancestral tail, the coccyx, at the base of his spine. In the human embryo, the very muscles for wagging this tail are still found. In adult man, these muscles are represented, as a rule, by bands of fibrous tissue. Occasionally, however, the dissecting surgeon finds these muscles well developed in the body of a man or woman. Science says that evolution alone can explain this lingering relic of a tail, with its attendant muscles, in the human body.