CHAPTER XIII SEX AND SOCIETY Only the chemist can tell, and not always the chemist, What will result from compounding Fluids or solids. And who can tell How men and women will interact On each other, or what children will result? Their son a devastating fire. Sex in Lower Organisms -EDGAR LEE MASTERS The first hint of sex in the organic world appears to be in the close association and subsequent separation of the chromosomes of unicellular organisms. Sometimes this is accompanied by an exchange of material. Some of these unicellular forms occasionally unite, trade material, separate again. Rejuvenation appears to result. As yet there is no sex. A step higher on the ladder of life and we come to the protozoan Volvox where vast numbers of cells unite in colonies. Some of these cells grow to great size and break away from the old associates to form new colonies. In some cases certain cells divide and preface cells equipped with whip-lash tails which then conjugate with other type of cells and thus start a new colony. The eg the sperm cells minute. "One volvox, theref unisexual or hermaphroditic-it is neither male normale, As the ova themselves can form complete colonies without the need of fertilization, the volvox is also parthenogenetic (virgin reproduction). In short, volvox, as Geddes says, is an 'epitome of the evolution of sex'." 1 Nature appears to be experimenting. Plant lice have a generation in which both sexes are present, followed by several generations in which there are no males. The hickory phylloxera has a curious history. In the spring females only appear and lay their eggs in a leaf ball. These eggs may be either large or small but from the large eggs females only are hatched; from the small eggs, males only. After fertilization these females lay the large eggs which last over the winter to renew the cycle the next spring. In the plant world many species bear perfect flowers while others have only male or female flowers. There seems to be no other difference in these latter species. The only possible explanation is that this is a device to secure cross-fertilization which involves inheritance from two lines. Some lowly animal forms like snails, leeches and earthworms are hermaphroditic, i.e., producing both male and female cells, and this condition is believed to occur even in birds and mammals. Sex Differentiation The first great difference between the sexes, then, lies in the fact that they arise from fertilized eggs with a certain chromosome content and that later they produce only ova or sperms as the case may be. The sperms are among the smallest of cells while the ova may be a hundred sand times larger. The sex organs constitute the second set of differences. Closely associated with these, though the causal connection is far from clear, are the differences in other organs of the body. The male spider is a pygmy in comparison with its mate. The plumage of the male bird contrasts with the more demure colors of the female. There is no uniformity in these differences. Externally the male and female kingfishers are almost identical, as are the rabbits. Yet in mammals these differences hark back to the very early fetal stages. Quite possibly they are produced by hormones secreted by certain glands of the body or by the influence of the germ cells themselves. This is an involved and difficult problem about which biologists are much perplexed. Finally there may be differences in the emotions and intellect, either caused by or associated with some of the other differences just mentioned. These differences will show themselves in behavior rather than in structure. The possible differences between the sexes, then, appear to be: 1. Germ cells 2. Sex organs 3. Endocrine glands 4. Other organs of the body 5. Emotional and intellectual equipment The unfertilized eggs of the bee develop into drones, but the fertilized eggs produce the workers and queens. The difference between the two last appears to be a question of food only. This indicates that actual development depends on conditions. There is much reason to believe that even in man we have to do with an asexual body which develops male or female characteristic depending on the stimuli present. Sometimes in insects, and rarely in birds, individuals are found where one side of the body is of the female type, the other, of the male. A bullfinch has been found which had on one side of its breast the red feathers of the cock and on the other, the brown feathers of the hen, the two sharply separated. Castrated animals do not wholly lose earlier characters but do tend to approximate a halfway stage between the two sexes. Relative Numbers of Males and Females Accepting the idea that sex is determined by the presence or absence of certain genes in the germ cells, and recalling the fact that one sperm unites with one egg, we might anticipate that in all forms of life the numbers of the two sexes would be about equal. This is far from true. In some nematode worms there are over one hundred females to one male, though here the females are really hermaphrodites. Bees and wasps produce few males. Matings of guinea fowl and pheasants have produced 74 males to 13 females, and crosses between different species of the same genus have shown 72 males to 18 females. Hybrids often show an excess of males. Even in human beings there is no absolute equality. About one hundred and five boys are born to every one hundred girls in modern society. Our figures are not wholly accurate for different countries; still they agree in the main: England, 103.6; France, 104.6; Germany, 105.2; Spain, 108.3; United States, 106. If stillborn infants are included the ratio is higher: Germany, 128.3; Italy, 131.1; and France, 142.4. If abortions are counted the difference appears to be still greater. We do not know how to explain these returns though explanation is possible without surrendering the belief in sex determination by chromosomes. Assuming the substantial accuracy of the figures just given, the death rate of males in fetal life is higher than that of the females. The same holds true in later life. In the first four months of pregnancy 180 males were lost to a hundred females, according to one student of the returns from Paris. Taking the last year reported in a recent study of infants during the first year of life, the number of boys dying to each hundred of girls was: England and Wales, 128; Sweden, 123.7; United States, 129.2; Australia, 131; New Zealand, 134.7; Baden, 138.1. All the facts point to the male as the frailer sex. From the earliest embryos in which distinctions of sex are readily traced, through the precarious period of infancy and even into advanced years, natural selection discriminates against the male. It is only in the child bearing period, and in some countries not even then, that the death rate of women is, on the average, higher than that of men. To a certain extent in adult life, and to a large extent in the periods of infancy and ante-natal development, the higher mortality of the male is doubtless an expression of his inherent inferiority in constitutional origin or vitality. In early infancy his vitality is relatively lower than that of the female and only gradually approaches it in later years. The causes of the greater difference in early infancy are internal and constitutional, and not external or adventitious. The external conditions are practically the same for both male and female infants in early infancy as they are also in prenatal life. If one goes over the 189 causes of death listed in the volumes of the United States Mortality Statistics, he cannot fail to be impressed with the relatively high male mortality in infancy from practically all causes. Even accidents are more fatal to males than to females. With the single striking exception of whooping cough and the somewhat doubtful exception of gonococcus infection, all of the causes of death which affect infancy take a relatively high toll of the male sex, and this discriminating death rate continues for most causes of death through several years of childhood. There can scarcely be any other explanation of this than that the male is handicapped by lessened degree of vitality that is directly or indirectly the result of his peculiar complex of hereditary factors.3 Without discussion of causes we may note that this inequality exists in all age periods and that it is not until the age of seventy is past that women outnumber men in the United States. Sex Determination The starting point of all differences between the sexes, is then in the original germ cells. These germ cells are increased by ordinary division like other cells. They also go through a maturing division in which the process is somewhat |