. Biology in America. Biology. 228 Biology in America which Professor Wilder calls '' cosmobia.'' Thus in man there exists a whole series of duplicities from a slight cleft of the spinal cord to those in which the cord is doubled for its entire length and is more or less rudimentary. The doubling process may go furtber, resulting in a double-headed monster, or one with two heads and four arms. Or if the process proceed in the reverse direction a single body and head may possess tAvo pairs of legs; while if the doubling process occur at both ends simultaneously "Siamese twins" result;
. Biology in America. Biology. 228 Biology in America which Professor Wilder calls '' cosmobia.'' Thus in man there exists a whole series of duplicities from a slight cleft of the spinal cord to those in which the cord is doubled for its entire length and is more or less rudimentary. The doubling process may go furtber, resulting in a double-headed monster, or one with two heads and four arms. Or if the process proceed in the reverse direction a single body and head may possess tAvo pairs of legs; while if the doubling process occur at both ends simultaneously "Siamese twins" result; until finally if the body be completely separated "identical twins". Cyclopean Pish Produced by treatment with magnesium salts. From Stockard, in "Journal Experimental Zoology," Vol. 6. Mouth; yolk sack. occur, which are always of the same sex, and resemble each other as closely as the proverbial "two peas in a ; The experiments on fish embryos strongly support the theory of Mall, that monstrosities in man are due to diseased conditions in the mother's uterus, with resultant metabolic disturbances and the formation of toxins in the embryo and fetus. We have seen in the last chapter that our present evidence very strongly indicates that sex is predetermined in the egg, so that most of the supposed instances of its artificial control are at the present time of historical interest only. One of the most popular tbeorios of sex determination ascribes to food a sex determining influence. Experiments of this nature have. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Young, R. T. (Robert Thompson), b. 1874. Boston, R. G. Badger
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