Ryder.] [May 16, the female is merely a retarded stage of the development of the male may be correlated with the singular and suggestive contrasts between the egg and spermatozoön. The evolution of sex and the evolution of sexual love or passion are inextricably intertwined. The history of the one is the history of the other. There are many reasons leading to the conclusion that the earliest and lower forms of sexuality were never in the past and are not now impelled to conjugate by anything akin to the gratification of passion such as is met with amongst the higher series of animal forms. Sexual passion is the outgrowth of a gradually developed and increased capacity for experiencing pleasurable sensations by the parent body or soma which is the producer or bearer of the sexual products. The high specialization of the sexual processes in higher forms has also unfortunately led to the possibility of their perversion. No sexual perversion is possible amongst lower forms where the essence of sexuality is the mere concrescence or conjugation of sexual cells. Courtship, violence towards and pursuit of the female, sexual love, etc., are the consequences of the evolution of a soma or parent body, which is the mere carrier of germ-cells, but which is capable of experiencing exquisite pleasure in the consummation of the sexual act. The intromission of an erectile organ covered with highly sensitive nervous end-organs into the genital passages of the female is the appetency for the sexual elements to conjugate reflected upon the soma. Copulation and the development of erectile or other sensitive intromittent and reciprocally coadapted primary sexual organs must have been due to the effect of use, since disuse, as in castration, affects the development of the parts, while abnormal activity, under favorable conditions, is said to increase their development. This view is sustained by the evidence in both plants and animals; in both the devices for effecting conjugation of the sexual elements and developed in the most gradual manner, until, in plants, the pollen-grains, with the help of various secondary adaptations, such as their morphological development, insect agency, the wind, etc., are evolved into true intromittent organs answering to the function of a penis in the form of a growing pollen-tube, stimulated to growth by nutriment supplied by the stigma and carrying the very minute, elongate, male chromatin element in its very narrow passage to the ovicell of the ovary. In the same way the male intromittent organs of animals have been developed from a mere cloacal papilla, or a low-grooved fleshy erectile process to a highly differentiated and excessively complex penis with, in some cases, an elaborate series of rosettes and flanges covered with a thin integument with highly sensitive terminal sensory nerves, that are in reflex connection with the higher parts of the sensorium and through the lumbar region of the spinal cord with the testes, spermatic vesicles and accelerator urinæ and other muscles which they may throw into spasmodic contractions in order to compress the vesiculæ and cause the emission of the male elements in the act of coition. Similar actions result in the female which 1890.] [Ryder. affect the peristaltic contraction of the oviducts, the enclosure of the Ovary by the fimbria leading to conditions favorable to the emission of the egg at the time of coitus. In animals, the provisions for rendering the male elements more efficient are thus rendered more perfect. There is not wanting evidence that the glans penis may serve as a sort of piston, fitting closely against the sides of the vaginal passages so as to prevent the regurgitation and loss of the semen. In mice I have observed that in those which have recently been in coitus, the uterus is actually distended with semen. These contrivances, many of which are of the most singular conformation, as that of the pig, for example, probably serve the purpose of more efficiently carrying the seminal matter into the genital passages of the female where they are to subserve the essential purposes of reproduction. At any rate, the wonderful contrivances in the higher plants serving the purpose of efficient fertilization are no more remarkable than those in the higher animals, the study of which has been singularly neglected by physiologists. In the lowest types of living forms there is nothing which suggests in any way the gratification of passion. The mere tendency towards conjugation of animals and plants without nerves cannot be identified with an appetency arising from any pleasure experienced in such conjugation. There are at first no provisions made for conjugation except such as the accident of contiguity of the conjugating elements as the germinating spores of Myxomycetes, the intracellular spores of Hydrodictyon, etc. When the process is so primitive as this, there is no evidence to show that it is anything more than the expression of the cessation of one order of things at the termination of one set of external conditions giving place to a new order of things under the stimulus of a new set of outward conditions more favorable to growth. Under this view of the case the incipiency of conjugative phenomena is simply the expression of a readjustment of the processes of growth under the influence of more or less favorable conditions of life. The physiological traits of that life are expressed in the mode of molecular aggregation and constitution of the cellular unit or units composing the individual. Its tendencies are to increase the mass of the individual by processes of integration of new matter in the course of which such new matter becomes molecularly identical with that of the organism engaged in such integration, a process commonly expressed by the term assimilation. The consequence of such newer integrations are that still other integrations are possible, under favorable conditions, on a much larger scale than the first ones. The increased power to make continuously more and more extensive and rapid integrations of identical molecules is possibly in some way due to the increase of mass and surface and the consequently increased capacity to liberate energy, or to perform work in a still more active integration and assimilation of molecules. The Malthusian principle therefore rests, in its last analysis, upon a PROC. AMER. PHILOS. SOC. XXVIII. 132. R. PRINTED MAY 27, 1890. Ryder.] [May 16, chemico-physical basis. It is probably, therefore, not an unjustified assumption to state that the acquisition of an increased mass in organic bodies leads to an increased capacity to integrate and assimilate still further additions to the original organized mass, and that if this process could go on indefinitely without the intervention of death and a necessity for oxygen, the earth might be gradually transformed, in so far as its available materials held out for such a purpose, into a few organized individuals. Such a supposition is, however, absurd, since such masses, even were their growth possible, would finally become helplessly immobile from their own weight; such a process would be self-destructive and incapable of indefinite maintenance. If, however, the principle that successive increments in the mass of organized bodies, carries with it the implication that such increments imply their capacity to increase more and more rapidly, under favorable conditions, or as it may otherwise be expressed, are thus enabled to grow, in virtue of such an inherent property, far beyond the bulk of their original germinal mass, then this deduction must form the basis upon which the phenomena of growth, reproduction and sex must finally be interpreted. This principle affords also the physico-chemical or physiological reason for the foundation of the Malthusian principle that the production of organisms would if unchecked outrun the available food production for a certain section of such organisms, as an aggregate-namely, the animal world. The foundation of the principle of Malthus and of the Darwinian principle founded upon it, therefore lies within the domain of ultimate biological physics or the molecular dynamics of organized bodies. The mainspring of the principle of natural selection, upon final analysis is not itself a choice between two things but an inevitable consequence of the innate molecular habit of living matter, if I may so express myself. It is physical in that the chemical and physiological laws under which growth or molecular integration can take place are themselves resolvable into physical laws which can be coördinated under the principle of the conservation of energy. This physical principle of continuous and continuously augmented integration and the consequent increase of the mass of living bodies is the primary conditioning factor of growth by intussusception of similar molecules. It initiates the struggle for existence, as the struggle due to motion and the attraction of stellar bodies, maintains the latter in their harmonious relations in space. This principle must, however, be further qualified in that the properties of the molecular integrating factors of living organisms differ very widely. Some forms (vegetal) under one set of conditions can integrate new and more complex assimilable molecules by recombining binary compounds; other forms-animals-can assimilate only such new ternary molecules or such as are very nearly similar to their own, while a third form, the sexual, is probably the highest expression of this integration of similar mole cules in that here the molecular differences are zero or nearly so, and at most goes no further than molecular differences, having their origin in the individual traits of either of the two parents. The last or sexual form of integration or intussusception also occurs, en masse, and without any reciprocal sacrifice of molecular identity. This last form of organic molecular integration is therefore effected with the least expenditure of energy on the part of the sexual elements themselves which are involved. Sexuality according to this view as expressed primarily in conjugation is a sort of refined hunger, in which neither the "eating" nor the "eaten " expends but a minimum of energy in a process of reciprocal assimilation. It is a hunger in which the sense of "taste" in the vulgar, anthropo morphic sense is unknown; it is an affinity developed possibly through the attraction of identical molecular aggregates for each other. The principle of cumulative molecular integration is similar in some respects to the cumulative principle operative in organic structural evolution, through which a superposition of adaptations results, not necessarily as the consequence of selection but as the result of the morphological and physiological necessity of conforming in the next step of morphological and physiological complication to that which had preceded it. Many instances in illustration might be cited, such as the annular placenta of the ovum necessarily conforming to the easiest possibility of internal contact with a tubular uterine canal. This principle has been responsible for much that has happened in organic evolution, but it is again dependent in curious, circuitous ways upon the still more primary principle of cumulative integration, overgrowth of organisms, or their capacity to grow beyond their own bulk at certain points, as implied by Haeckel. The highest form of cumulative integration ending in an overgrown and abortive spermatogonium, which is the equivalent of the egg, together with its further expression in the production of spermatozoa which have had their cytoplasmic field reduced, leads to a condition where the one becomes helpless without the other. It also presumably leads to the evolution of an appetency or affinity of the male for the female element in that the one possesses what the other does not, and in that they are produced in similar organisms or those of the same species their idioplasmic constitution must be very nearly the same, except for the morphological differences which characterize them. These differences are again the preponderance of nucleoplasm in the one or the element immediately concerned in growth and the physiological integrity of the living cell, and the preponderance of cytoplasm in the other, which is the medium in which free nuclear motion, karyokinesis, and consequent growth is possible. The affinity so developed through cumulative integration by the divergent processes of ovogenesis and spermatogenesis ends in what I shall term reciprocal integration without loss of molecular identity, or in what is usually termed "fertilization." The advantages offered by such a process is that it provides for the development of metazoan or multicellular embryo, which is without the Ryder.] [May 16, need of immediately feeding, but which is enabled to reach a certain selfhelpful morphological complication before it begins the struggle for existence for itself. It provides a large cytoplasmic field in which rapidly recurrent successive and simultaneous karyokineses can take place under the guidance of the inherited tendencies resident in the nucleoplasm and cytoplasm of the combined germs. The one sex appears to supply the field for segmentational activity, the other the segmentational impulse itself. In other words, sexuality is the expression of the action of the principle of the physiological division of labor, extended so as to involve two kinds of individuals of the same species, or two different functionless parts of the same individual, as in hermaphrodites. There is no convincing evidence that the male induces variability. The argument from hybrids is of little value. The tendency to an equilibrium as the consequence of close interbreeding or of continued promiscuous interbreeding is the same, and is to be interpreted as the result of the constancy of the mode of growth of the average individual which must finally result, following from the average of hereditary characters which are finally thus transmissible. As soon as slightly differing forms are crossed the karyokinetic equilibrium is disturbed and variability ought on a priori grounds to ensue. To saddle the induction of variability upon the male does not seem to be demonstrated, as the factors involved are too numerous to enable us to decide what ones are important and what are unimportant. A view which has far more in its favor is that a large oösperm, interpreted as above, with a large cytoplasmic field, is inherently more liable to vary its karyokinetic processes through very slight variations in the external influences than a small or a parthenogenetic one. That sexuality, taken in the widest sense, is responsible for variability is probably nearer the truth. That the oösperm, with its large cytoplasmic field, is the real arena in which variability disports itself, may be taken for granted. It is aiso very evident that the evidence derived from the development of monsters is clearly in favor of such a view. Monsters are developed only when the early stages of development are karyokinetically disturbed, as is well known. Moreover, there is no hard and fast line between monstrosities and variations of a less and less monstrous character until those of an almost imperceptible and unimportant character are encountered. That the tendency towards variability is more marked in the young than in the adult stages of fixed and slightly variable types of Metazoa may be regarded as a truism, and must be considered the foundation of these views. In that temperature affects the rate of karyokinetic processes, it is clear that inequalities of temperature simultaneously affecting different points on the surface of an egg would affect the rate of segmentation of the cells of such different points and thus induce variability. A single karyokinesis disturbed or impeded on one side of an embryo must disturb all subsequent ones. A mechanism so delicate as this of karyokinesis may |