Nothing is more conspicuous in recent years than the growth of sensibility on the subject of economic evils, especially as to the conditions of industry. Economic efficiency, as a sole object, appeared to preclude regard to morality of method, and the result has been poverty for the masses of mankind. If this is to cease, satisfactory minimum standards of comfort and welfare for the entire population must be accepted, which will form a first charge on industry. This can only be hoped for when there is complete practical acceptance of the fact that “we are members one of another,” and servitude is completely replaced by the ideal of mutual service. (_c_) The Malthusian hypothesis ignores the great though paradoxical truth, that although under circumstances permitting malnutrition and defective training, large families spell poverty, especially when population is not distributed where it is needed, the real wealth of the world after all depends on man himself. Nature gives him little that he can use in the form in which he finds it. It is by him and by him alone that “wealth” is created by converting useless into useful matter. It appears to me clear that over-population need not excite apprehension; that population in itself is the only means by which national wealth can materialise; and that our chief aim in securing national efficiency must be to train each unit of the population adequately for work, and to prevent the terrible loss of efficiency due to avoidable sickness. And this brings me to the direct statement of the truism that health progress can only be secured by preventing preventible illness. Poverty and disease are allied in the closest relationship; and while it is true that the removal of poverty would effect a great improvement in national health, it is even truer that the prevention of illness forms the most important means for the avoidance of poverty. In various reports it has recently been shown that in a number of districts an inverse correlation exists between infant mortality and the amount of the family income; the implication appearing to be that increase of the lower income is the best and perhaps the only method for obviating excessive loss of infantile life. In such an argument poverty evidently is considered as an element, instead of as a highly complex phenomenon needing to be further analyzed into its constituent parts. In the instance quoted, the fact that the correlation between poverty and high infant mortality is not essential can be shown by examples of low infant mortality in communities in which poverty is the rule; by examples of high infant mortality in which wages are high; and by other examples of communities in which high infant mortality has been lowered without any change in economic conditions.