The problems of industrialism in relation to health cannot be adequately discussed apart from a consideration of the remuneration for work, which necessarily depends on the power of the worker to strike a satisfactory bargain with his employer, and the extent to which he can ensure regular employment. If these conditions cannot be fulfilled, or if the breadwinner is dead or disabled, poverty results, using this word here in the sense of inability to provide for the personal and family essentials of health. And here we are at once faced with the problem of relation of population to means of subsistence. Malthus in 1798 advanced the pessimistic hypothesis that poverty is the inevitable result of increase of population, which entitles him to be characterised as the Schopenhauer of Political Economy, as Schopenhauer was the Malthus of Philosophy. Without attempting detailed discussion of Malthus’s hypothesis, it is clear that the wealth of the population depends upon 1. The amount of food produced, 2. The amount of materials produced, 3. The efficiency in preparation of these materials, and 4. Convenience of transport. In all these particulars means of subsistence, considered internationally, have during the last century grown more rapidly than population; and now, whether we like it or not, a new element has entered into the problem in this and several other countries,—voluntary control of births,—necessitating the estimation of future growth of population on a radically different basis from that of the past, and banishing the fear of poverty as the result of too large a population. It may even become necessary to adopt some method of national remission of taxation or subsidisation of wages in accordance with size of the family, not only in France, but hereafter in England, if in England, as already in France, the voluntary control of births is practised to an extent resulting in a stationary or even a decreasing population. In America the possible need for such action will not arise for several generations, during which, however, unless the present trend of events is changed, Roman Catholics appear likely largely to replace Protestants, and the Slavonic and Irish to preponderate over the Anglo-Saxon elements of the population. It is possible, of course, that in another generation the Roman Catholic Church may not be able to continue its ban on birth-control, and that the more “backward” (?) races will adopt similar devices, including even the Japanese and the Chinese. _The Malthusian Hypothesis_