The Sexes in Science and History. Eliza Burt Gamble
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it is manifested. By those who have observed the laws which govern the manifold changes in matter, the fact is declared that the various manifestations in form and substance constitute the only creation of which we may have any knowledge; and, moreover, that the genesis of existence is going on as actively in our time as at any previous period in the history of matter. So far as human knowledge extends, no particle of matter has ever been created and none ever destroyed. This continuous process of transmutation of substance and change of form, in other words the phenomena designated Life, may have been in operation during all the past, and may continue forever.
As all speculations concerning the origin of matter have been unavailing, so all attempts to solve the problem of the origin of life have proved futile. The experiments recently carried on in the Rockefeller Institute, in which by means of chemical processes detached organs from the bodies of animals have been made to perform their normal functions, are interesting and instructive, but these experiments furnish no clue to the origin of the force which animates living organic matter. Why the nucleated cells which we call a heart should pulsate whilst those which we call a liver should secrete bile, nobody knows.
That all life on the earth has been derived from one, or at most from a few original forms, is said to be proved by ontogeny, or the history of the germ, which in its development passes through a number of the forms which mark the ascending scale of life.
Through the study of comparative anatomy, the fact has been discovered that the individuals composing the various orders of the great vertebrate series are all moulded “on the same general plan”; that up to a certain stage in the development of the several germs—for instance those of the man, the ape, the horse, the dog, etc.—they are not distinguishable the one from the other, and that it is only at a later stage of development that they take on the peculiarities belonging to their own special kind. The number and variety of forms which appear in the animal and vegetable world make it difficult to conceive of the idea that all have sprung from one, or at most from a few original types, yet the chain of evidence in support of this theory seems quite complete.
Natural Selection, by which it is demonstrated that organized matter must move forward simply through the chemical and physical forces inherent in it, furnishes a key to all the phenomena of life, both animal and vegetable, which have ever appeared on the earth. Natural Selection, we are told, depends for its operation on the interaction of two processes or agencies, namely, Inheritance and Adaptation. Through Inheritance germs receive from their parents a plastic form which, as all development is a function of external physical conditions, is itself nothing more than a “manifestation of the remains of antecedent physical impressions.” This inherited form causes them to go forward in a predestined course, while through Adaptation there is a constant tendency to change that predestined form imposed upon them by their parents to one better suited to their changing physical conditions.
According to the theory of Natural Selection, organic structures vary to meet the requirements of changed conditions; or, when existing circumstances are such that they are forced into new and unusual modes of life, they branch off into different directions; thus new varieties are formed, or possibly new species. Such portions of a group, however, as remain sheltered from conditions unsuited to their present line of development, retain their ancient forms. This change of structure by which organisms or portions of organic bodies are modified so as to perform more complicated functions, or those better suited to their environment, is denominated differentiation; hence the degree of differentiation attained by a structure determines the stage of development which it has reached.
But to return to our single-celled animal—the simplest form of life on the earth. Except that by the action of the surrounding forces its surface has become somewhat hardened, this little animal is the same throughout, in other words, it is homogeneous. The hardening of the outer portion constitutes the first process of differentiation, and therefore the first step in the order of progress.
Comparing the simplest form of life, the little carbon-sac found in the sea, with the germ from which animals and plants are derived, Haeckel says:
Originally every organic cell is only a single globule of mucus, like a Moneron, but differing from it in the fact that the homogeneous albuminous substance has separated itself into two different parts, a firmer albuminous body, the cell-kernel (nucleus), and an external, softer albuminous body, the cell-substance or body (protoplasma).3
From its body, which, when at rest, is nearly spherical, it is almost constantly casting forth certain “finger-like processes” which are as quickly withdrawn, only to reappear on some other portion of its surface. The small particles of albuminous matter with which it comes in contact adhere to it, or are drawn into its semi-fluid body by displacement of the several albuminous particles of which it is composed, and are there digested, being “absorbed by simple diffusion.” Its only activity consists in supplying itself with nourishment, and even during this process it is said to display a negative or passive quality rather than real action. The particles absorbed that are not assimilated, are expelled through the surface of the body in the same manner as they are taken into it.
At first, we are told, our animal is only a simple cell, in fact that it is not a perfect cell, for as yet the cell-kernel or nucleus has not been separated from the cell-substance or protoplasm. When its limit of size has been reached it multiplies by self-division, or by simply breaking into parts, each part performing the same functions of nutrition and propagation as its predecessor. Later, however, when a parent cell bursts, the newly developed cells no longer separate from it, but, by cohering to it and to each other, form a cluster of nucleated cells, while around this aggregation of units is formed a wall. Still its food is absorbed. Subsequently, however, a mouth and prehensile organs for seizing its food are developed, and the divisions between the cells are converted into channels or pipes through which nourishment is conveyed to every part of the body. In process of time, limbs for locomotion appear, together with bones for levers, and muscles for moving them. Finally, a brain and a heart are evolved, and although at first the heart appears as only a simple pulsating vessel, later this animal finds itself the possessor of a perfect system of digestion, circulation, and excretion, by which food, after having been changed into blood and aërated or purified by processes carried on in the system, is pumped to every part of the body. With the formation of different chemical combinations, and the development, through increasing specialization of the various kinds of tissues, and finally of the various organs, that intimate relationship observed between the parts in homogeneous and less differentiated structures no longer exists; hence, in response to the demand for communication between the various organs, numberless threads or fibres begin to stretch themselves through the muscles, and collecting in knots or centres in the brain and spine, establish instantaneous communication between the different parts, and convey sensation and feeling throughout the entire organism.
A division of labour has now been established, and each organ, being in working order and fashioned for its own special use, performs its separate functions independently, although its activity is co-ordinated with that of all other organs in the structure.
This far in the history of life on the earth sex has not been developed, or, more correctly stated, as the two sexes have not been separated, our animal is still androgynous or hermaphrodite—the reproductive functions being confined in one and the same individual. Within this little primeval animal, the progenitor of the human race, lay not only all the possibilities which have thus far been realized by mankind, but within it were embodied also the “promise and potency” of all that progress which is yet to come, and of which man himself, in his present undeveloped state, may have only a dim foreshadowing.
From the time of the appearance of life on the earth to that of the separation of the sexes, myriads of centuries may have intervened. Only when through a division of labour these elements became detached, and the special functions of each were confided to two distinct and separate individuals, did the independent history of the female and male sexes begin.
No fact is more patent, at the present time, than that sex constitutes the underlying principle throughout nature. Although it may not be said of the simplest forms of life that sexual difference has been established, yet we are assured that among the ciliated Infusorians “male and female nuclear elements have been distinguished.” This primitive condition,