Sex and Society | Page 3

able to give us. Researches must be carried farther on the effect of temperature, light, and water on variation, before we may hope to reach a positive conclusion. We can only assume that the chemical constitution of the organism at a given moment conditions the sex of the offspring, and is itself conditioned by various factors--light, heat, water, electricity, etc.--and that food is one of these variables.[15] It is sufficient for our present purpose that sex is a constitutional matter, indirectly dependent upon food conditions; that the female is the result of a surplus of nutrition; and that the relation reported among the lower forms persists in the human species.
In close connection with the foregoing we have the fact, reported by Maupas,[16] that certain Infusorians are capable of reproducing asexually for a number of generations, but that, unless the individuals are sexually fertilized by crossing with unrelated forms of the same species, they finally exhibit all the signs of senile degeneration, ending in death.[17] After sexual conjugation there was an access of vitality, and the asexual reproduction proceeded as before. "The evident result of these long and fatiguing experiments is that among the ciliates the life of the species is decomposed into evolutional cycles, each one having for its point of departure an individual regenerated and rejuvenated by sexual copulation."[18]
The results obtained by Maupas receive striking confirmation in the universal experience of stock-breeders, that, in order to keep a breed in health, it is necessary to cross it occasionally with a distinct but allied variety. It appears, then, that a mixture of blood has a favorable effect on the metabolism of the organism, comparable to that of abundant nutrition, and that innutrition and in-and-in breeding are alike prejudicial.
If this is true, and if heightened nutrition yields an increased proportion of females, we ought to find that breeding-out is favorable to the production of females, and breeding-in to the production of males; and a considerable body of evidence in favor of this assumption exists.[19]
Observations of above 4,000 cases show that, among horses, the more the parent animals differ in color, the more the female foals outnumber the male. Similarly, in-and-in-bred cattle give an excessively large number of bull calves. Liaisons produce an abnormally large proportion of females;[20] incestuous unions, of males.[21] Among the Jews, who frequently marry cousins, the percentage of male births is very high.
According to Mr. Jacobs' comprehensive manuscript collection of Jewish statistics ... the average proportion of male and female Jewish births registered in various countries is 114.5 males to 100 females, whilst the average proportion among the non-Jewish population of the corresponding countries is 105.25 males to 100 females.... His collection includes details of 118 mixed marriages; of these 28 are sterile, and in the remainder there are 145 female children and 122 male--that is, 118.82 females to 100 males.[22]
The testimony is also tolerably full that among metis and among exogamous peoples the female birth-rate is often excessively high.[23]
Viewed with reference to activity, the animal is an advance on the plant, from which it departs by morphological and physiological variations suited to a more energized form of life; and the female may be regarded as the animal norm from which the male departs by further morphological variations. It is now well known that variations are more frequent and marked in males than in females. Among the lower forms, in which activity is more directly determined mechanically by the stimuli of heat, light, and chemical attraction, and where in general the food and light are evenly distributed through the medium in which life exists, and where the limits of variation are consequently small, the constitutional nutritive tendency of the female manifests itself in size. Among many Cephalopoda and Cirripedia, and among certain of the Articulata, the female is larger than the male. Female spiders, bees, wasps, hornets, and butterflies are larger than the males, and the difference is noticeable even in the larval stage. So considerable is the difference in size between the male and female cocoons of the silk-moth that in France they are separated by a particular mode of weighing.[24] The same superiority of the female is found among fishes and reptiles; and this relation, wherever it occurs, may be associated with a habit of life in which food conditions are simple and stimuli mandatory. As we rise in the scale toward backboned and warm-blooded animals, the males become larger in size; and this reversal of relation, like the development of offensive and defensive weapons, is due to the superior variational tendency of the male, resulting in characters which persist in the species wherever they prove of life-saving advantage.[25]
The superior activity and variability of the male among lower forms has been pointed out in great detail by Darwin and confirmed by others.
Throughout the animal kingdom, when