For long people believed the plant louse truly androgynous. Réaumur and Bonnet, having seen isolated plant-lice reproduce themselves were convinced of this, when Trembley, a man of genius, celebrated also for his observations of hydra, threw out the idea: Who knows whether a coupling of these lice does not fecundate them for several generations? He had discovered the basis of parthenogenesis. Facts upheld him. Bonnet described the male and female, and noted even the genital ardour of this sticking leaf-louse, this milch-cow of the ants.
Parthenogenesis is a sign-post. Nothing more clearly demonstrates the importance of the male or the precision of his function. The female appears to be the whole show, without the male she is nothing. She is the machine and has to be wound up to go. The male is merely the key. People have tried to obtain fecundation by false keys. Eggs of sea-anemones, and star-fish have been hatched by contact with exciting chemicals, acids, alkalines, sugar, salt, alcohol, ether, chloroform, strychnine gas, carbonic acid. But one has never been able to bring these scientific larvæ to maturity, and everything leads one to believe that if one succeeded, and that if these artificial beings were capable of reproduction, it would be but for a limited period. This provoked parthenogenesis is neither more nor less interesting than the normal. It is doubtless abnormal, but abnormal parthenogenesis is not infrequent in nature; eggs of the bombyx, of star-fish, and of frogs, hatch sometimes without fecundation, and very probably because they have accidentally come up against the very stimulant which the excellent experimenters have lavished on them. Whether sperm acts as an "excitant" or as fecundator, the action is no easier to understand by one label than by another. The queen bee lays both fecundated and non-fecundated eggs; the first hatch female, the second invariably male, here the male element would seem to be the product of parthenogenesis and the female to require previous fecundation. In contrast, among plant-lice, the generations of female continue for nearly two years. There is an order in these things, as in all things, but it is not yet apparent; one notes only, that however long and varied be the parthenogenetic period, it is limited somewhere by the necessity of the female principle being united with the male principle. After all, hereditary fecundation is no more extraordinary than particular fecundation, it is a mode of perpetuating life which the exercise of one's reason should make one consider as perfectly normal.
One ought, at the end of this summary chapter, to be courageous enough to say that fecundation, as vulgarly understood, is merely an illusion. Taking man and woman (or no matter what dioic metazoaire) the man does not fecundate the woman; what happens is at once more mysterious and more simple. From the male A, the great Male, and from the great Female B are born without any fecundation whatever, spontaneously, little males a and little females 6. These little males are called spermatozoides, and the little females, ovules; it is between these new creatures, between these spores, that the fecundating union occurs. One then observes that a and b resolve themselves into a third animal x, which by natural growth becomes either A or B. Then the cycle begins again. The union between A and B is merely a preparation; A and B are nothing but channels carrying a and b, carrying them often far beyond themselves. Like the plant-lice or drones, the mammifers called man are subject to alternate generation, one parthenogenesis always separating the veritable conjunction of the differentiated elements. Coupling is not fecundation; it is merely the mechanism; its utility is merely in that it puts two parthenogenetic products into relation. This relation occurs inside the female, or outside the female (as in case of fishes); the milieu has an importance of fact, not of principle.
CHAPTER IV
SEXUAL DIMORPHISM
I. Invertebrates: formation of the male.—Primitivity of the female.—Minuscule males: the bonellie.—Regression of the male into the male organ: the cirripedes.—Generality of sexual dimorphism.—Superiority of the female in most insect species.—Exceptions.—Numeric dimorphism.—Female hymenoptera.—Multiplicity of her activities.—Male's purely sexual rôle.—Dimorphism of ants and termites.—Grasshoppers and crickets.—Spiders.—Coleoptera.—Glow-worm.—Cochineal's strange dimorphism.
I. Invertebrates.—At a moment fairly undecided in the general evolution the male organ specializes into the male individual. Religious symbolisms may or might have been intended to mean this. The female is primitive. At the third month, the human embryo has external uro-genital organs clearly resembling the female organs. To arrive at complete female estate they need undergo but a very slight modification; to become male they have to undergo a considerable and very complex transformation. The external genital organs of the female are not, as has been often said, the product of an arrested development; quite the contrary, the male organs undergo a supplementary development, which is moreover useless, for the penis is a luxury and a danger: the bird who does without it is no less wanton thereby.
One finds general proof of the female's primitivity in the extreme smallness of certain male invertebrates, so tiny indeed that one can only consider them as autonomous masculine organs, or even as spermatozoides. The male of the syngames (an internal parasite of birds) is less a creature than an appendix; he remains in constant contact with the organs of the female, stuck obliquely into her side, and justifying the name "two-headed worm" which has been given to this wretched and duplex animalculus. The female bonellie is a sea worm shaped like a sort of cornucopia sack fifteen centimetres in length: the male is represented by a minuscule filament of about one or two millimetres, that is to say about one-thousandth her size. Each female supports about twenty. These males live, first in the œsophagus, then descend into the oviduct where they impregnate the eggs. Only their very definite function clears them from the charge of being parasites; in fact they were long supposed to be parasites, while men sought vainly for the male of the prodigious bonellie.
Side by side with males who are merely individualized sexual organs, one sees males who have lost nearly all organs save the male organ itself. Certain hermaphrodite cirripedes (mollusks attached by a peduncle [stalk]) cling as parasites to the coat of other cirripedes: whence a diminution of volume, a regression of ovaries, abolition of nutritive functions; the stalk takes root in the living, nourishing milieu. But one organ, the male one, persists in these diminished cirripedes, and takes on enormous proportions, absorbing the whole of the animal. With only a slight further change one would see the transformation of male into male organ completely accomplished, as one does, moreover, in the hydraria. Become again an integral part of an organism from which it had formerly separated to become an individual, the male merely returns, to its origins and clearly certifies what they were.
The bonellie, which is one of the most definite examples of dimorphism, is also an example of the singular feminism which one normally finds in nature. For feminism reigns there, especially among inferior species and in insects. It is almost only among mammifers and in certain groups of birds that the male is equal or superior to the female. One would say that he has slowly attained a first place not intended by nature for him. It is probable that, relieved of all care, after the fecundation, he has had more leisure than the female wherein to develop his powers. It is also possible, and more probable, that these extremely diverse cases of resemblance and dissemblance are due to causes too numerous and too varied for us to seize their logical sequence. The facts are obvious: the male and the female differ nearly always, and differ often profoundly. Many insects vulgarly supposed to be different species are but males and females of one race seeking each other for mating. It needs some knowledge to recognize a pair of blackbirds, the male black all over, and the female brown-backed with grey throat and russet belly.
While hermaphrodism demands a perfect resemblance of individuals—save in cases