It would be unsafe to draw specific conclusions about mammals from these bird and insect experiments. Both the secretory action and the chromosome mechanisms are different. The quant.i.tative nature of s.e.x, and also the existence of inters.e.xual types, between males and females, would seem to be general phenomena, requiring rather slight corroboration from the mammals themselves. We have such mammalian cases as the Free-Martin cattle, and some convincing evidence of inters.e.xuality in the human species itself, which will be reviewed presently.

The notion of more "developmental energy" or a higher metabolism in males is borne out in the human species. Benedict and Emmes[7] have shown by very careful measurements that the basal metabolism of men is about 6% higher than that of women. Riddle cites the work of Thury and Russell on cattle to show that a higher water value (as he found in the pigeon eggs), a.s.sociated with increased metabolism, helps to produce males.

In males, the secretion of the s.e.x glands alone seems to be of particular importance, again suggesting this idea of "strength" which comes up over and over again. Removal of these glands modifies the male body much more profoundly than it does the female.[8] It is quite generally supposed that the action of this one secretion may have much to do with the superior size and vigour of males. For example, Paton says[9]: "The evidence thus seems conclusive that in the male the gonad, by producing an internal secretion, exercises a direct and specific influence upon the whole soma, increasing the activity of growth, moulding the whole course of development, and so modifying the metabolism of nerve and muscle that the whole character of the animal is altered." It used to be said that the male was more "katabolic," the female more "anabolic." These expressions are objectionable, inasmuch as they hint that in a mature organism, with metabolism rather stable, tearing down, or katabolism, could go on faster than building up, or anabolism, or that one of two phases of the same process might go on faster than the other. It seems safer to say merely that a lower metabolism in the female is accompanied by a tendency to store materials.

A long time will doubtless be required to work out the details of differences in metabolism in the two s.e.xes. Some of the main facts are known, however, and the general effects of the two diverse chemical systems upon the life cycles of the s.e.xes are quite obvious. What we call the "quant.i.tative theory of s.e.x" has, besides a place in exact science, an interesting relation to the history of biological thought, especially as applied to society. It is thus in order to state as clearly as possible what it now is; then, so that no one may confuse it with what it is not, to run over some of the old ideas which resemble it.

Experiments with transplanted s.e.x glands, with s.e.x-gland extracts (testicular and ovarian) and the observation of infusions of a male-type blood-stream into a female body, as occurs in nature in some cattle and in the so-called human "hermaphrodites," indicate a gross chemical difference between the respective determiners for femaleness and for maleness. So the chemicals involved, though not yet isolated, must be presumed to be _qualitatively_ different, since they produce such different results.

But such experiments also indicate that both determiners must be present in some proportions in every individual of either s.e.x. The basis for both s.e.xes being present, the one which shall predominate or be expressed in the individual must depend upon the _quant.i.tative_ relation between the determiners which come together at fertilization. The quant.i.tative theory merely means that this predominance of one factor or the other (maleness or femaleness--Gynase or Andrase) is more p.r.o.nounced in some cases than in others.

In brief, then, the quant.i.tative theory of s.e.x is merely the most reasonable explanation of the known fact that inters.e.xes exist--that is, females with some male characteristics, or with all their characters more like the female type than the average, and _vice versa_. Laboratory biology has established the phenomena of inters.e.xuality beyond question, and the word "inter-s.e.x" has become a scientific term. But the fact that this word and the idea it represents are new to _exact science_ does not mean that it is new in the world.

Inters.e.xes in the human species--not only the extreme pathological cases represented by the so-called "hermaphrodites," but also merely masculine women and effeminate men--have been the subject of serious remarks as well as literary gibes from the earliest times. The Greeks called these people _urnings_. Schopenhauer was interested in the vast ancient literature and philosophy on this subject. The 19th century produced a copious psychological treatment of warped or reversed s.e.xual impulses by such men as Moll, Krafft-Ebing and Havelock Ellis. Otto Weiniger[10]

collected a ma.s.s of this philosophy, literature, psychology, folklore and gossip, tied it together with such biological facts as were then known (1901) and wove around it a theory of s.e.x _attraction_.[A] The same material was popularized by Leland[11], Carpenter[12] and W.L.

George[13] to support quite different views.

[Footnote A: NOTE: Weiniger thought he could pick, merely by observing physical type, people who would be s.e.xually attracted to each other.

There is much ground for scepticism about this. To begin with, the biological experiments indicate that inters.e.xes are peculiarly likely to appear where two or more races are mixed. So far, there is no exact knowledge about the amount or kind of s.e.x difference in each race. As Bateson remarks (Biol. Fact & the Struct. of Society, p.13), one unversed in the breeds even of poultry would experience great difficulty and make many mistakes in sorting a miscellaneous group of c.o.c.ks and hens into pairs according to breed. If this is true in dealing with pure breeds, "in man, as individuals pure-bred in any respect are very rare, the operation would be far more difficult." In the human species s.e.xual attraction also obviously depends upon many factors which are not purely biological; it is rather a complicated sentiment than an instinct.]

George's statement that "there are no men and ... no women; there are only s.e.xual majorities"[p.61, op. cit.] has been widely quoted. The feminists, he adds, "base themselves on Weininger's theory, according to which the male principle may be found in woman, and the female principle in man." Unfortunately, George does not make clear what he means by "principle," so his theory, if he has one, is impossible to appraise in biological terms. From the embryonic idea expressed above, he deduces a very positive social philosophy of s.e.x. The feminists, he says, "recognize no masculine or feminine '_spheres_' and ... propose to identify absolutely the conditions of the s.e.xes." So, while George seems to think much more highly of women than does Weininger, their philosophies come together, for quite different reasons, on the practical procedure of disregarding reproduction and letting the race go hang[10, p.345]. Weininger seems to recognize the dual basis for s.e.x; George evidently does not quite follow him. Both entirely misconceived the real issues involved, as well as the kind of evidence required to settle them, as we shall see later in discussing adaptation and specialization.

Dr Blair Bell[14,15] has collected a ma.s.s of evidence on inters.e.xes in the human species. This includes his own surgical and other cases, as well as many treated by his colleagues, and a very considerable review of the medical literature. He not only believes in degrees of femininity in women, but has worked out cla.s.sifications which he claims to have found of great practical value in surgery.[14, pp.166-7] As noted above, Riddle discovered that his more feminine female pigeons were often killed by a dose of testicular extract which was practically harmless to a partially masculinized female. s.e.x in the human species being a matter of all the glands organized into a complex, the quant.i.tative "strength"

of that complex would be useful to know before removing any one secretion from it. Dr Bell states that the ooph.o.r.ectomy operation (removal of ovaries) may be performed upon a masculine type of woman with "little disturbance of the metabolism..." But he thinks that the degree of masculinity should always be carefully observed before undertaking such operations, which in some cases have most undesirable effects.

At one end of the scale, this surgeon places the typically feminine woman in all her characteristics--with well-formed b.r.e.a.s.t.s, menstruating freely and feminine in instincts--he says "mind." The intermediate grades consist, he says, of women whose metabolism leans toward the masculine type. Some have s.e.xual desires but no maternal impulse. Others desire maternity but take no interest in s.e.x activity, or positively shun it. The physical manifestations of masculine glandular activity take the form of pitch of voice, skin texture, shape and weight of bones, etc. Some of the inter-grades are a little hard to define--the human species is such an inextricable mixture of races, etc.; but Dr Bell does not hesitate to describe the characteristically masculine woman of the extreme type, who "shuns both s.e.xual relations and maternity...(She) is on the fringe of femininity. These women are usually flat-breasted and plain. Even though they menstruate, their metabolism is often for the most part masculine in character: indications of this are seen in the bones which are heavy, in the skin which is coa.r.s.e, and in the aggressive character of the mind...If a woman have well-developed genitalia, and secondary characteristics, she usually is normal in her instincts. A feebly menstruating woman with flat b.r.e.a.s.t.s and coa.r.s.e skin cannot be expected to have strong reproductive instincts, since she is largely masculine in type..."

The glandular and quant.i.tative explanation of s.e.x, instead of being abstruse and complicated, brings the subject in line with the known facts about inheritance generally. The dual basis for femaleness and maleness in each individual simply means that both factors are present, but that only one expresses itself fully. The presence of such a dual basis is proved by the fact that in castration and transplantation experiments both are exhibited by the same individual in a single lifetime. In the case of the Free-Martin cattle, even the female s.e.x-glands are modified toward the male type to such an extent that they were long mistaken for testes. The same applies to some glands found in human "hermaphrodites," as Dr Bell's plates show.

The peculiar complication of the chemical complex determining s.e.x in these mammalian forms, involving all the glands and hence the entire body, makes it problematical whether a complete (functional) reversal is possible, at least after any development whatever of the embryo has taken place. On the other hand, the fact that such complete transformations have not so far been observed by no means proves their non-existence. Their being functional, and hence to all external appearances normal, would cause such animals to escape observation.

Latent traits of the opposite s.e.x of course immediately suggest recessive or unexpressed characters in the well-known Mendelian inheritance phenomena. In the bird-castration cases, we saw that to remove the inhibiting s.e.x glands caused previously latent characters to act like dominant or expressed ones. The case of horns in sheep, investigated by Professor Wood[16], is so similar that it seems worth summarizing, by way of ill.u.s.tration.

Both s.e.xes in Dorset sheep have well-developed horns; in the Suffolk breed both s.e.xes are hornless. If the breeds are crossed, all the rams in the first (hybrid) generation have horns and all the ewes are hornless. If these hybrids are mated, the resulting male offspring averages three horned to one hornless; but the females are the reverse of this ratio--one horned to three hornless. This is an example of Mendel's principle of segregation--factors may be mixed in breeding, but they do not lose their ident.i.ty, and hence tend to be sorted out or segregated again in succeeding generations.

In the horned Dorsets, we must suppose that both males and females carry a dual factor for horns--technically, are _h.o.m.ozygous_ for horns. The hornless Suffolks, on the contrary, are h.o.m.ozygous for _absence_ of horns. Thus the dual factor in the zygotes or fertilized eggs at the basis of the first filial (hybrid) generation consists of a single factor for horns and a single factor for their absence. If we represent horns by _H_ and absence of horns by _A_, Dorsets have a factor _HH_, Suffolks _AA_ and the hybrids _HA_.

All the males in this generation have horns, which means that a single "dose" of the factor _H_ will produce horns in a male, or that they are _dominant_ in males. But a single dose will not produce horns in a female--that is, horns are _recessive_ in females--the factor is present but unexpressed.

Mating two _HA_ hybrids, the _H_ and _A_ of course split apart in the formation of the gametes, as the _HH_ and _AA_ did in the previous generation; so that we get an equal number of single _H_ and _A_ factors. In reuniting in fertilized eggs, the chance is just half and half that an _H_ will unite with another _H_ or with an _A_--that an _A_ will unite with an _H_ or another _A_. Thus we have two chances of getting _HA_ to each chance of getting either _AA_ or _HH_. Half the zygotes will be _HA_, one-fourth _HH_ and one-fourth _AA_.

If we consider four average males, one will have two _A's_ (absence of the factor for horns) and will thus be hornless. One will have two _H's_, or the double factor for horns, and hence will exhibit horns--as will also the two _HA's_ since a single dose of horns expresses them in a male. So we have the three-to-one Mendelian ratio.

But four females with exactly the same factors will express them as follows: The one _HH_ (double factor for horns) proves sufficient to express horns, even in a female. The _AA_, lacking the factor entirely, cannot have horns. Nor will the two _HA_ females have horns, a single dose being insufficient to express them in a female. Again we get our three-to-one Mendelian ratio, but this time it is three hornless to one horned.

Especially Goldschmidt's carefully graded experiments point to a similar difference in the strength of the dose or doses of the s.e.x factors.

Instead of the two doses of horns required to express them in the presence of the female secretory balance in Professor Wood's sheep, Goldschmidt found it took six doses of maleness to completely express it on a female basis in his moths. But even with three doses, the female was incapable of reproduction. A single dose in excess of the ordinary combination to produce normal females modified the type of body, also reducing the number of eggs.

In the case of the horns, only two types were possible, absence or presence of the character. Likewise there are only two types of primary s.e.x, i.e., of s.e.x glands proper. But seven different types or grades of body for each s.e.x were found to exhibit themselves in the moths. In more complicated bodies, we should of course expect many more, and where many races (instead of two) are mixed, as in man, a cla.s.sification merely on the basis of physical characteristics would be much more complicated.

Indeed, we may well be sceptical as to the possibilities of cataloguing differences of the sort between men and women by body type alone.

In society, however, we are much more interested in the mental than the purely physical qualities of the two types of bodies, especially since the use of machines has so largely replaced brute strength with skill.

Most employments do not even require a muscular skill beyond that possessed by ordinary individuals of both s.e.xes.

Even this ignores the primary consideration in the s.e.x problem in society, the first of the following two parts into which the whole problem may be divided: (1) _How to guarantee the survival of the group through reproduction_ of a sufficient number of capable individuals; and (2) How to make the most economical use of the remaining energies, first in winning nutrition and protection from the environment, second in pursuing the distinctly human values over and above survival. The s.e.x problem as a whole is concerned with adjusting two different general types of individuals, male and female, to the complicated business of such group life or society. The differences between these two s.e.x-types being fundamentally functional, the best way to get at them is to trace the respective and unlike life cycles.

We have already shown in rude outline how a difference (apparently chemical) between two fertilized eggs starts them along two different lines of development in the embryonic stage. One develops the characteristic male primary and secondary s.e.x characters, the other the female. Throughout the embryonic or intra-maternal stage this differentiation goes on, becoming more and more fixed as it expresses itself in physical structures. Childhood is only a continuation of this development--physically separate from the mother after the period of lactation. Until p.u.b.erty, when s.e.x ceases to be merely potential and becomes functional (about 12-14 in girls and 14-16 boys), the differences in metabolism are not very marked. Neither are they in old age, after s.e.x has ceased to be functional. It is during the period when s.e.x is functional (about 35 years in women and considerably longer in men) that the gross physiological differences manifest themselves.

Before p.u.b.erty in both s.e.xes, calcium or lime salts are retained in the tissues and go to build up the bony skeleton. (A mere sketch of calcium metabolism is all that can be given here--for details consult such works as 15 and 17 in bibliography; summary in 14; pp. 34f. & 161f.) Note that p.u.b.erty comes earlier in girls than in boys, and that the skeleton therefore remains lighter. During the reproductive period in women these salts are heavily drawn upon for the use of the reproductive system. The male reproductive system draws upon them as well, though the drain is very slight as compared to that in women. In old age these salts produce senility through deposit in the tissues, especially in the arteries.

At the p.u.b.ertal age in girls begins the phenomenon known as menstruation, in which there is a large excretion of calcium salts. In pregnancy these are needed for building the skeleton of the foetus, and at delivery go to the b.r.e.a.s.t.s to a.s.sist in lactation. Bell states that there is a noticeable connection between early menstruation and short stature, and _vice versa_. What is commonly known as menstruation lasts only a few days, and is merely the critical period in a monthly cycle or periodicity which goes with the female s.e.x specialization. This period involves the gradual preparation of the uterus or womb for a guest, together with the maturing of the ova. Then the Graafian follicles containing the ova break and these latter enter the uterus for fertilization.

If fertilization takes place, the fertilized egg buries itself in the wall and development of the embryo proceeds. Menstruation stops, the calcium salts being required for the growing embryo. There is likely to be no menstruation for a considerable time after delivery if the child is nursed, as is normal. This gives the uterus time for devolution to the normal, before a surplus of calcium salts sets the periodicity going again. If the egg which pa.s.ses from the ovary to the uterus is not fertilized, it is excreted, the uterus goes through another monthly cycle of preparation for the period of intra-maternal environment, and so on indefinitely until the climacteric.

This climacteric or decay of s.e.xuality is a rather critical time, especially in women. It marks the period at which the metabolism can no longer support the strain of reproduction. A surplus of calcium brings on senility, as noted above. Withdrawal of the interests which centre in s.e.x, together with the marked accompanying physical changes, involves a shift of mental att.i.tude which is also frequently serious. A British coroner stated in the _British Medical Journal_ in 1900 (Vol. 2, p.792) that a majority of 200 cases of female suicide occurred at this period, while in the case of younger women suicide is peculiarly likely to occur during menstruation. Krugelstein and Lombroso, respectively, remark the same tendencies.[18]

It is a matter of almost everyday observation that men and women in the neighbourhood of fifty suddenly find themselves disoriented in the world. Tolstoi, for example, who had written pa.s.sionately of pa.s.sion in his earlier years, suddenly awoke, according to his "Confessions," from what seemed to him afterward to have been a bad dream. In this case, the result was a new version of religion as a new anchorage for the man's life. It may be pacifism, prohibition, philanthropy, or any one of a very large number of different interests--but there must usually be something to furnish zest to a life which has ceased to be a sufficient excuse for itself.

If freed from worry about economic realities, it is not infrequently possible for the first time for these people to "balance" their lives--to find in abstraction a rounded perfection for which earlier in life we seek in vain as strugglers in a world of change. Thus old people are often highly conservative, i.e., impatient of change in their social environment, involving re-orientation; they wish the rules of the game let alone, so they can pursue the new realities they have created for themselves.

Socially, the old are of course a very important factor since a changed metabolism sets them somewhat outside the pa.s.sionate interests which drive people forward, often in wrong directions, in the prime of life.

Hence in a sense the old can judge calmly, as outsiders. Like youth before it has yet come in contact with complicated reality, they often see men and women as "each chasing his separate phantom."

While such conservatism, in so far as it is judicial, is of value to society, looking at it from the viewpoint of biology we see also some bad features. _Senex_, the old man, often says to younger people, "These things you pursue are valueless--I too have sought them, later abandoned the search and now see my folly;" not realizing that if his blood were to resume its former chemical character he would return to the quest.

Elderly people, then, biological neuters, come especially within the problem of the economical use of the social as distinguished from the biological capacities of the race. They affect the s.e.x problem proper, which applies to a younger age-cla.s.s, only through their opinions. Some of these opinions are hangovers from the time in their own lives when they had stronger s.e.xual interests, and some are peculiar to people of their readjusted glandular activity. Their reproductive contribution to society has been made.

Pre-p.u.b.ertal childhood and youth, on the contrary, has its biological contributions to society still before it. The glandular activity of boys and girls is perhaps not so unlike as to justify society in giving them a different kind of education and preparation for group life. The excuse for two sorts of training is that the two s.e.xes will not do the same work after p.u.b.erty. Hence the question of youthful training is sociological almost entirely--not biological--or rather, it rests upon the biology, not of childhood but of the reproductive period, which society antic.i.p.ates.

Instead of scattering attention over the whole history of the universe, then, or even over the general field of biology, in dealing with s.e.x as a social problem, the emphasis must be upon the human life cycle during the functional-reproductive period. Other biological data than that which concerns this period is merely introductory or explanatory. The extent to which the sociological problem involved is linked up with general biological considerations like natural selection, adaptation and specialization will be summarized in a separate chapter.

Earlier female maturity and p.u.b.erty, as well as lighter structure, have already been accounted for by the metabolism, especially of the calcium salts. These have also been shown to be the key fact in the monthly periodicity of the mammalian female. Nearly all of the anatomical and physiological s.e.x differences catalogued by such pioneer workers as Ellis, Ploss, Thomas and Bucura are simply what we should expect from the less active and in some ways peculiar metabolism of woman.

Among such differences are the size and shape of bones and other body structures, the more plentiful haemoglobin in male blood during the reproductive period, and such blood peculiarities as the production of more carbonic acid or the higher specific gravity in the male. The greater percentage of fat as compared with muscle in women[19], if it is generally true, is what we should expect from a lower metabolism and a tendency to store materials. The long list of diseases which are more or less s.e.x-limited [20; 14, pp.160f.; 18] are largely endocrine. Even those which do not primarily concern the internal secretory system would be expected to work somewhat differently in the presence of unlike blood streams. As to the greater average weight of the male brain, this is true of the whole body. Brain weight, either absolute or relative to body weight, is not positively known to be in any way correlated (in normal people) with mental capacity.

A library might be stocked with the vast literature devoted to summarizing and cataloguing s.e.x differences; and most of it would be useless from the standpoint of sociology. Unaccompanied by the criticisms a biologist would have to make on the method of their ascertainment and validity, not to mention their significance, such lists can easily do--and probably have done--more harm than good. One simple and reasonable criterion would reduce this catalogue to fairly modest proportions, so far as social science is concerned: _Which ones have an obvious or even probable social significance?_ Over and above that, while such contrasts may be of speculative interest, they lead imaginative people to argue from them by a.n.a.logy and thus cloud the real issues.

What are the outstandingly significant s.e.x differences which application of the above criterion leaves? (1) A less active and more uneven metabolism of woman; (2) a.s.sociated with this, less physical strength on the average--hence an inferior adaptability to some kinds of work, resulting in a narrower range of choice of occupation, disadvantageous in compet.i.tive society; (3) But the one fundamental difference, to which all the others are as nothing, is the specialization of the mammalian female body and metabolism to furnish the intra-maternal environment (approximately nine months in the human species) for the early development of the young and lactation for some months afterward.

This last may be said to include the former two, which were arbitrarily placed first because they are always in evidence, whether reproduction is undertaken or not. This takes us out of cell and endocrine biology and into the general problem in group adjustment to environment which that specialization entails.

BIBLIOGRAPHY FOR CHAPTER III

1. Goldschmidt, R. Experimental Inters.e.xuality and the s.e.x Problem.

Amer. Naturalist, 1916. Vol. 50, pp. 705f.

2. Goldschmidt, R. Preliminary Report on Further Experiments in Inheritance and Determination of s.e.x. Proc. Nat. Acad. Sc, 1916.

Vol. II, No. 1, pp. 53f.