. Biology in America. Biology. 230 Biology in America been performed on insects, frogs, birds and mammals. Better nutrition is supposed to produce more females and vice versa. In this way the attempt has been made to explain the increase in males in France during the Napoleonic wars. One observer has cited data showing that among the nobility of Sweden the proportion of males to females is 98-100, while among the clergy the ratio is Another has shown on the contraiy that in London the more well-to-do have a larger percentage of sons than daughters. Temperature, age of parents and ri
. Biology in America. Biology. 230 Biology in America been performed on insects, frogs, birds and mammals. Better nutrition is supposed to produce more females and vice versa. In this way the attempt has been made to explain the increase in males in France during the Napoleonic wars. One observer has cited data showing that among the nobility of Sweden the proportion of males to females is 98-100, while among the clergy the ratio is Another has shown on the contraiy that in London the more well-to-do have a larger percentage of sons than daughters. Temperature, age of parents and ripeness of eggs are other popular factors in sex determination. But one of the most naive of recent theories supposes that there is a regular alternation of male. A Human "Monster " Courtesy of Dr. Oeo. L. Streeter. and female producing ova in man, the former coming from the right, and the latter from the left ovary, and that sex might be determined by the position of the prospective mother, whether lying on her right or left side. Extensive experiments have been conducted on the influ- ence of external factors in determining the sex cycle in par- thenogenetic animals. The most familiar example of this type' is the bee, in which the unfertilized egg gives rise to a male (drone) and the fertilized to a female (queen) or an unde- veloped female (worker). Here sex depends upon the act of fertilization, and is probably determined by the chromosomes, which differ in number in the two sexes. The influence of food in controlling development is here most beautifully. 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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