[123] The recognition of this relationship must not be regarded as an attempt unduly to narrow down the causation of changes in the birth-rate. The great complexity of the causes influencing the birth-rate is now fairly well recognized, and has, for instance, been pointed out by Goldscheid, _Hoeherentwicklung und Menschenoekonomie_, Vol. I, 1911. [124] In a paper read at the Brunswick Meeting of the German Anthropological Society (_Correspondenzblatt_ of the Society, November, 1898); a great many facts concerning the fecundity of women among savages in various parts of the world are brought together by Ploss and Bartels, _Das Weib_, Vol I, chap. XXIV. [125] The proportion of doctors to the population is very small, and the people still have great confidence in their quacks and witch-doctors. The elementary rules of sanitation are generally neglected, water supplies are polluted, filth is piled up in the streets and the courtyards, as it was in England and Western Europe generally until a century ago, and the framing of regulations or the incursions of the police have little effect on the habits of the people. Neglect of the ordinary precautions of cleanliness is responsible for the wide extension of syphilis by the use of drinking vessels, towels, etc., in common. Not only is typhoid prevalent in nearly every province of Russia, but typhus, which is peculiarly the disease of filth, overcrowding, and starvation, and has long been practically extinct in England, still flourishes and causes an immense mortality. The workers often have no homes and sleep in the factories amidst the machinery, men and women together; their food is insufficient, and the hours of labour may vary from twelve to fourteen. When famine occurs these conditions are exaggerated, and various epidemics ravage the population. [126] It must, however, be remembered that in small and unstable communities a considerable margin for error must be allowed, as the crude birth-rate is unduly raised by an afflux of immigrants at the reproductive age. [127] Arsene Dumont, _Depopulation et Civilisation_, 1890, chap. VI. The nature of the restraint on fertility has been well set forth by Dr. Bushee ("The Declining Birth-rate and its Causes," _Popular Science Monthly_, August, 1903), mainly in the terms of Dumont's "social capillarity" theory.