THE 



POPULAR SCIENCE 

 MONTHLY. 



OCTOBEE, 1884. 



THE SIGNIFICANCE OF HUMAN ANOMALIES. 



By FEANCIS J. SHEPHERD, M. D. 



EVER since tlie study of human anatomy has attracted any atten- 

 tion, variations in the aiTangement of the different structures 

 of the body have been noticed. For many centuries, the signification 

 of these variations was not understood ; and even as lately as 1840, Dr. 

 Knox, of Edinburgh, who had the courage to state his conviction that 

 they connected man with the lower animals, was looked upon, even by 

 members of his own profession, as one prompted by the evil-one. In 

 early times, when great prejudice existed against the dissection of 

 human bodies, and animals, such as monkeys, dogs, cats, etc., were 

 frequently used as substitutes, the similarity of some of their muscles 

 to those which occasionally occurred in man as anomalies, forced the 

 anatomists to remark on them as being curious coincidences, though 

 in their published works they drew no conclusions from their occur- 

 rence bearing on the origin of man. 



In the view of our present knowledge of the animal kingdom and 

 its development, and with the acceptance of the great principle of 

 evolution, the explanation of these variations is simple enough, viz., 

 that they point to the fact that man has descended from some lower 

 form, and " is the co-descendant with other mammals of a common 

 progenitor" (Darwin). 



Again, many structures which in man are merely rudiments and 

 quite useless, nay, sometimes a source of danger, are seen fully per- 

 fected in some of the lower animals, and in them fulfill a definite pur- 

 pose. The existence of such rudimentary organs (or, as Haeckel calls 

 them, "worthless primeval heirlooms") as the ear-muscles, the ap- 

 pendix vermiformis in the intestines, the thyroid gland, the remnant 

 VOL. XXV. — 46 



