Suppose, next, a species whose individuals have great powers of self-preservation, while they have powers of multiplication much beyond what is needful. The excess of fertility, if extreme will cause sudden extinction of the species by starvation. If less extreme, it must produce a permanent increase in the number of the species; and this, followed by intenser competition for food and augmented number of enemies, will involve such an increase of the dangers to individual life, that the great self-preserving powers of the individuals will not be more than sufficient to cope with them. That is to say, if the fertility is relatively too great, then the ability to maintain individual life inevitably becomes smaller, relatively to the requirements; and the inverse proportion is thus established."

Two points of special interest for our present and subsequent considerations should be noted in connection with this argument. In the first place, we should observe that the maintenance of the inverse. relationship between Individuation and Genesis is due to the action of the destructive forces of the environment: these destructive forces consisting principally of enemies, who may directly attack and kill the individual members of the species, and of the shortage of food (or other necessaries), which may indirectly reduce the numbers of the species by allowing a certain proportion of the individual members to perish through want of adequate sustenance; this latter factor being (as Malthus has so convincingly shown) the one predominantly effective in reducing numbers in the human race.

Secondly, we may draw from Spencer's principle the corollary that a more rapid multiplication in any species must (other things remaining the same and within certain limits) bring in its train greater difficulties in the way of preservation of the individual life; while if the species takes to multiplying less rapidly, this will (with similar reservations) cause a corresponding reduction of the forces destructive of the individual, who will therefore enjoy a safer and a longer life. This corollary is of obvious importance in its application to the human race, where the rate of multiplication is to some extent directly under volitional guidance and where in consequence it would appear that in birth control we possess a potent weapon for rendering the individual human being longer-lived, more amply provided with the necessaries of life and less. exposed to the rigours of the struggle for existence; in other words for attaining those ends which the majority of social and political reformers have principally in view. That the corollary is true in fact has been shown by the evidence of vital statistics, which reveal a high positive

correlation between birth rates and death rates throughout the world, indicating that a high degree of exercise of the reproductive powers tends to be associated with a relatively high degree of danger to the individual life1.

Spencer's second a priori argument, as already indicated, treats the matter from the point of view of the internal economy of the individual, and although of somewhat lesser interest from the biological and sociological points of view, is perhaps of even greater importance as regards the psychological aspects of the antagonism between Individuation and Genesis. The matter and energy which go to the formation of a new individual are withdrawn from the parent or parents and are therefore not available for enrichment of the parents' life, as they otherwise might be. This is very evident in the case of lowly organisms with whom reproduction takes the form of a simple budding off from the body of the parent; where it is clear that the more frequent the budding off and the larger the portions budded off, the greater is the amount of matter energy subtracted from the parent organism. In higher organisms, with their various methods of sexual reproduction, the same relation holds, though considerably obscured by the complexities in which the antagonism between Individuation and Genesis now manifests itself.

and

1 Our knowledge of the existence and significance of this correlation we owe largely to Dr C. V. Drysdale, whose important sociological work, published unfortunately in somewhat inaccessible form, is far less known than it deserves to be. Cf. The Small Family System, Fifield, 1913; Wages and the Cost of Living, 1913; Diagrams of International Vital Statistics, and the series of papers on "The Malthusian Doctrine and its Modern Aspects in The Malthusian, 1916 and 1917 (the three last being published by the Malthusian League). By his statistical work Dr Drysdale has shown that in practically all countries rises and falls in the birth rate are accompanied by corresponding rises and falls in the death rate, so that a decrease in the number of births (such as has taken place in the last forty years or so in most civilised countries) has been accompanied by a more or less proportionate decrease in the death rate; that countries with stationary birth rates have more or less stationary death rates, and that the few countries which have shown a rise of birth rate have also shown a rise of death rate. These correspondences afford strong confirmation of the Malthusian position that each country can only support a certain limited (though under modern-pre-war-conditions, usually increasing) population, and that when by an unduly high birth rate the population endeavours, as it were, to increase beyond the limits imposed by biological and economic causes, the result is an increase in the death rate that cancels the effect of the high birth rate, so that the total population (or increase of population) remains approximately the same. The apparent exceptions to the correspondence between birth and death rates really prove the rule-for these exceptions (there are only two) are Australia and New Zealand, the two countries with the lowest recorded death rates and (almost certainly) the smallest amount of poverty, showing that in these cases there does not exist the pressure of population upon the means of subsistence which appears to prevail to a greater or less degree in all other countries for which adequate vital statistics are obtainable.

The production of offspring always involves some sacrifice on the part of the parent, hence there always tends to be a negative correlation between the degree of parental development and the number of offspring produced. The sacrifice required of the parent may however affect one or more of several aspects of his existence, so that the inverse relation between parental development and production of offspring may not hold strictly of any one of these aspects, but only of the total quantity of energy constituting the life of the parent. The chief of these aspects as regards which the inverse relationship in question may manifest itself are: size, complexity of structure, degree and complexity of the activities of mind and body (i.e. amount of energy expended in vital functions); while, in addition to the expenditure involved in the actual production of offspring, there is also to be taken into account the nutritive material directly supplied to them from the parent's body, together with the energy expended in providing them with food from other sources and in protecting them from danger1.

Furthermore, the relationship is complicated by the fact that the absolute amounts of energy available for purposes both of Individuation and of Genesis depend upon the quantity and quality of nutriment obtainable by the parent, so that better fed individuals may, without any sacrifice of individual development, produce more offspring than the less well-fed individuals of the same species. As a further complication there should, strictly speaking, be considered, not only the number of offspring produced but also the size, quality etc. of this offspring: but as the size and quality of offspring are usually more or less proportional to the size and quality of the parents, this additional consideration can often be omitted in approximate comparisons-especially of course in comparisons between different species.

When all these complicating factors are taken into account, it appears that there must exist a very close inverse relationship between parental development and number of offspring, or in other words between the devotion of the available vital energy to purposes of individual life on the one hand or to purposes of propagation on the other. That this inverse relationship required by theory does exist in fact is shown by

1 It should be noted however that these two last-named factors are in one respect less opposed to Individuation than are the others; since, although the actions involved in the provision of food for the young or the protection of the young from danger are of no personal benefit to the parent, yet the muscular or mental capacities involved in these actions may be used for other purposes in which the individual does personally benefit. Thus a powerful muscular development in the parent may be of use both for the protection of offspring and for individual ends.

Spencer in his minute and painstaking review of the reproductive habits of animals at all levels of development-a review to which the final chapters of his Principles of Biology are devoted: so that in conclusion he is able to formulate the law "that every higher degree of organic evolution [as exhibited in the development of the individual] has for its concomitant a lower degree of that peculiar organic dissolution which is seen in the production of new organisms1."

That this law of the antagonism between Individuation and Genesis applies to human beings as well as to all other animals is shown by Spencer in the course of his review, and indeed this is abundantly clear without any special demonstration, both as a result of our previous considerations as regards the racial aspects of the antagonism and from the commonplace observations of everyday life; which show that parenthood almost always involves some (often very considerable) sacrifice of individual interests.

Vital statistics again afford us scientific proof that common observation is in this respect correct, for they reveal the fact that there is a very general inverse correlation between birth rate and social culture. Not only are the birth rates of relatively uncivilised nations as a rule considerably higher than those of their more civilised neighbours, but within a given community the birth rate of the poorer and less cultured classes is almost invariably higher than the birth rate among those who possess greater wealth and culture. This inverse relationship, which eugenists deplore, is indeed only a particular manifestation of the general law of the antagonism between Individuation and Genesis 2.

But in endeavouring to abolish this relationship, our modern social reformers of the biological school are not necessarily doomed to failure (though their task is perhaps more difficult than they imagine); for it would seem that mankind has indeed the power to establish such conditions that the operation of the law in human society will be far less 1 Op. cit. I. 472.

2 An important qualification should be added here. In virtue of the fact that the reproductive organs constitute a very essential part of the organism as a whole, healthy function of these organs is necessary for the health of the organism and any attempt to abolish or unduly to curtail their function is not to the advantage but to the disadvantage of the organism. Thus it is probable that the majority of women are-in spite of the sacrifices that maternity entails-capable of becoming on the whole and in the long run more efficient human beings as wives and mothers than as spinsters (cf. the increased health and beauty of so many women after-or even during-pregnancy); the same applying of course mutatis mutandis to the reproductive life of men. In the psychic sphere, the importance of this principle is now well recognised by psycho-analysts, who attribute much neurosis and consequent mental inefficiency to unsuccessful attempts at excessive sublimation.

stringent than has hitherto been the case, and that by the exercise of this power certain biological and economic factors through which the law now manifests itself can be partially or wholly withdrawn from its sphere of influence. Some of the problems connected with this possibility will be discussed in the concluding section of this paper.

III.

Hitherto we have dealt only with the nature of the relationship between Individuation and Genesis and have shown that this relationship must be inverse. We have said nothing as to the manner in which the ratio between Individuation and Genesis (which varies so enormously in different species) is established in any given case. And yet this problem is obviously of very great importance to us here; for Psycho-Analysis is interested above all in the dynamic and functional aspects of the mind and is concerned not only with the distribution of mental energy as it exists at any given moment, but also with the changes in this distribution that occur in the course of mental life-in the individual and in the race: or to put the matter in terms of our present problem, we are interested not only in the existing aspects of the struggle between the sexual tendencies and the self-regarding tendencies but also in the modifications which this struggle has undergone and is likely still to undergo in the course of evolution.

To the modern student of biology there can be little doubt that Natural Selection is the ultimate force at work in deciding what proportions of matter and energy shall be devoted to Individuation and to Genesis respectively in any given species, and what modifications (if any) the ratio between Individuation and Genesis shall undergo in the history of that species. To quote Spencer once more, we may say that "whether the interests of the species are most subserved by a higher evolution of the individual joined with a diminished fertility, or by a lower evolution of the individual joined with an increased fertility, are questions ever being experimentally answered. If the more developed and less prolific variety has a greater number of survivors, it becomes established and predominant. If, contrariwise, the conditions of life being simple, the larger or more organized individuals gain nothing by their greater size or better organization; then the greater fertility of the less evolved ones will insure to their descendants an increasing predominance1."

1 Op cit. II. 473. As Spencer points out in this connection, every successful modification in the direction of increased individuation "entails a decrement of reproduction that