required a population of only one in the time of our Saviour, it is necessary to insist upon the difference between increase and the power of increase.

One specific instance of this doubling process is sufficient to prove the power of increase possessed by a community, and the instance of the American Colonies, cited by Malthus, has never been denied.

A doubling of population in 25 years was thus looked upon by Malthus as the normal increase, under the most favourable conditions; but the checks to increase, vice, misery, and moral restraint are operative in varying degrees of intensity in civilized communities, and these may limit the doubling to once in 50, or once in 100 years, stop it altogether, or even sweep a nation from the face of the earth.

The natural increase among the lower animals is limited by misery only, in savage man by vice and misery only, and in civilized man by misery, vice, and moral restraint.

Misery is caused by poverty, or the need of food or clothing, and is thus proportionate to the means of subsistence. As the means of subsistence are abundant, misery will be less, the death-rate lower, and caeteris paribus the birth-rate higher. The increase will be directly proportional to the means of subsistence.

Vice as a check to increase, is common to civilized and savage man, and limits population by artificial checks to conception, abortion, infanticide, disease, and war. The third check, moral restraint, is peculiar to civilized man, and in the writings of Malthus, consists in restraint from marriage or simply delayed marriage.

Bonar says (Malthus and his Work, p. 53), "Moral restraint in the pages of Malthus, simply means continence which is abstinence from marriage followed by no irregularities."

These checks have their origin in a need for, and scarcity of food,—food comprising all those conditions necessary to healthy life. The need of food is vital and permanent. The desire for food, immediate and prospective, is the first motive of all animal activity, but the amount of food available in the world is limited, and the possible increase of food is estimated by Malthus at an arithmetical ratio.

Whether or not this is an accurate estimate of the ratio of food increase is immaterial. Malthus's famous progressions, the geometrical ratio of increase in the case of animals, and the arithmetical ratio of increase in the case of food, contain the vital and irrefutable truth of the immense disproportion between the power of reproduction in man and the power of production in food.

Under the normal conditions of life, the population tends constantly to press upon, and is restrained by the limits of food. The true significance of the word tends must not be overlooked, or a similar fallacy to that of Nitti's will occur, when he overlooked the significance of the term "power to multiply." It is perfectly true to say, that population tends to press upon the limits of subsistence, and unrestrained by moral means or man's reason actually does so.

Some social writers appear to think that, if they can show that production has far outstripped population, that, in other words, population for the last fifty years at least has not pressed upon the limits of food, Malthus by that fact is refuted.

Nitti says (Population and the Social System, p. 91), "But now that statistics have made such great progress, and the comparison between the population and the means of subsistence in a fixed period of time is no longer based upon hypothesis, but upon concrete and certain data in a science of observation it is no longer possible to give the name of law to a theory like that of Malthus, which is a complete disagreement with facts. As our century has been free from the wars, pestilences and famines which have afflicted other ages, population has increased as it never did before, and, nevertheless, the production of the means of subsistence has far exceeded the increase of men."

And later on (p. 114) he says "Malthus's law explains nothing just as it comprehends nothing. Bound by rigid formulas which are belied by history and demography, it is incapable of explaining not only the mystery of poverty, but the alternate reverses of human civilization."

Nitti's conclusions are based largely on the fact that while food supplies have become abundant and cheap, birth-rates have steadily and persistently declined.

No-one who has studied the economic and vital statistics of the last half century can fail to be impressed with the change that has come over the relative ratios of increase in population and food.

Bonar says (Malthus and his Work, p. 165), "The industrial progress of the country (France) has been very great. Fifty years ago, the production of wheat was only half of what it is to-day, of meat less than half. In almost every crop, and every kind of food, France is richer now than then, in the proportion of 2 to 1. In all the conveniences of life (if food be the necessaries) the increased supply is as 4 to 1, while foreign trade has become as 6 to 1."

In a remarkable table prepared by Mr. F.W. Galton, and quoted by Mr. Sydney Webb in "Industrial Democracy," it is clearly shown, that, while the birth-rate and food-rate (defined as the amount of wheat in Imperial quarters, purchased with a full week's wages) gradually increased along parallel lines between 1846 and 1877, the former suddenly decreased from 36.5 per thousand in 1877 to 30 per thousand in 1895, the latter increasing from .6 to 1.7 for the same period.

The remarkable thing about the facts that this table so clearly discloses is that with a gradual increase of the means of subsistence from 1846 to 1877 there is also a gradual increase in the proportion of births to population. But at the year 1877 there, is a very sudden and striking increase in food products, and the purchasing power of the people coincides exactly with a very sudden and striking decrease in the birth-rate of the people. The greater the decrease in the birth-rate, the greater the increase in the people's purchasing power. Now, what has brought about this change in the ratios of increase in population and in food respectively?

Some serious factor, inoperative during the thirty years prior to 1877 must have suddenly been introduced into the social system, to work such a marvellous revolution during the last twenty years.

Some economic writers find it easy here to discover a law, and declare that the birth-rate is in inverse ratio to the abundance of food. (Doubleday quoted by Nitti, Population and the Social System, p. 55).

Other economic writers of recent date attribute this great change in ratio of increase to economic causes. Only a few find the explanation in biological laws.

Herbert Spencer is the champion of the biological explanation of a decreasing birth-rate.

With the intellectual progress of the race there is a decadence of sexual instinct. In proportion as an individual concentrates his energies and attention on his own mental development, does the instinct to, and power of, generation decrease.

It may be true, it certainly is true, that if an individual's energies are concentrated in the direction of development of one system of the body, the other systems to some extent suffer. A great and constant devotion to the development of the muscular system will produce very powerful muscles, and great muscular energy, with a strong tendency to, and pleasure in exercise. It is true also, that time and energy are monopolized in this creation of muscle, and that less time and energy are available for mental pursuits and mental exercise.

Up to a certain point muscular exercise aids mental development, but beyond that point concentration of effort in the direction of muscular development starves mental growth.

On the other hand, if the education and exercise of the mind receive all attention, the