PART III: DOMESTIC INSTITUTIONS.

CHAPTER I: THE MAINTENANCE OF SPECIES.

§ 272. As full understanding of the social relations cannot be gained without studying their genesis, so neither can full understanding of the domestic relations; and fully to understand the genesis of the domestic relations, we must go further back than the history of man carries us.

Of every species it is undeniable that individuals which die must be replaced by new individuals, or the species as a whole must die. No less obvious is it that if the death-rate in a species is high, the rate of multiplication must be high, and conversely. This proportioning of reproduction to mortality is requisite for mankind as for every other kind. Hence the facts exhibited by living beings at large must be considered that the facts exhibited by human beings may be clearly comprehended.

§ 273. Regarding the continued life of the species as in every case the end to which all other ends are secondary (for if the species disappears all other ends disappear), let us look at the several modes there are of achieving this end. The requirement that a due number of adults shall arise in successive generations, may be fulfilled in variously-modified ways, which subordinate the existing and next-succeeding members of the species in various degrees.

Low creatures having small powers of meeting the life-destroying activities around, and still smaller powers of protecting Edition: current; Page: [604] progeny, can maintain their kinds only if the mature individual produces the germs of new individuals in immense numbers; so that, unprotected and defenceless though the germs are, one or two may escape destruction. And manifestly, the larger the part of the parental substance transformed into germs (and often most of it is so transformed), the smaller the part that can be devoted to individual life.

With each germ is usually laid up some nutritive matter, available for growth before it commences its own struggle for existence. From a given quantity of matter devoted by the parent to reproduction, there may be formed either a larger number of germs with a smaller quantity of nutritive matter each, or a smaller number with a larger quantity each. Hence result differences in the rates of juvenile mortality. Here of a million minute ova left uncared for, the majority are destroyed before they are hatched; multitudes of the remainder, with the feeblest powers of getting food and evading enemies, die or are devoured soon after they are hatched; so that very few have considerable lengths of individual life. Conversely, when the conditions to be met by the species make it advantageous that there should be fewer ova and more nutriment bequeathed to each, the young individuals, beginning life at more advanced stages of development, survive longer. The species is maintained without the sacrifice of so many before arrival at maturity.

All varieties in the proportions of these factors occur. An adult individual, the single survivor from hundreds of thousands of germs, may itself be almost wholly sacrificed individually in the production of germs equally numerous; in which case the species is maintained at enormous cost, both to adults and to young. Or the adult, devoting but a moderate portion of its substance to the production of multitudinous germs, may enjoy a considerable amount of life; in which case the cost of maintaining the species is shown in a great mortality of the young. Or the adult, sacrificing its substance almost entirely, may produce a moderate number Edition: current; Page: [605] of ova severally well provided with nutriment and well protected, among which the mortality is not so great; and in this case the cost of maintaining the species falls more on the adult and less on the young.

§ 274. Thus while, in one sense, the welfare of a species depends on the welfare of its individuals, in another sense, the welfare of the species is at variance with the welfare of its individuals; and further, the sacrifice of individuals may tell in different proportions on the undeveloped and on the mature.

Already in the Principles of Biology, §§ 319-51, the antagonism between Individuation and Genesis under its general aspects has been set forth. Here certain of its special aspects concern us. To comprehend them clearly, which we shall find it important to do, we must look at them more closely.