Within certain limits the death rate is more easily controlled than the birth rate. It is very difficult for society deliberately to set about to increase the birth rate, but it is comparatively easy for it to take deliberate measures to decrease the death rate, because all individuals have a selfish interest in decreasing the death rate; but the increase of the birth rate does not appeal to the self-interest of individuals. Modern medical science, as we have seen, has done much to decrease the death rate in civilized countries, and it promises to do even more. Fifty years ago a death rate of fifty or sixty per thousand population in urban centers was not unusual, but now a death rate of thirty to forty in a thousand in the same communities is considered an intolerable disgrace, and the time will shortly come, no doubt, when even a death rate of twenty per thousand of the population will be considered disgraceful to any community. As we have already seen, the normal death rate of the most enlightened European and American communities tends to establish itself around fifteen or sixteen.
Of course the sanitary and hygienic conditions which influence the death rate are so numerous that we cannot enter into and discuss them. We can only mention some of the more general social influences which are often overlooked and are of particular interest to the sociologist.
(1) The effect of war upon the death rate, particularly of the victorious, is not so great as many people suppose. Considerable wars are apparently often waged without very greatly increasing the number of deaths in a given population. This is, however, only true, as has already been said, of the victorious side. With the defeated it is far different. The death rate among the defeated in a modern war is oftentimes very greatly raised, but this is due not so much to the large number killed in battle as to the fact that the defeated have their territory invaded, their industries disturbed, and their general industrial and living conditions depressed. The vital statistics of France and Germany in the Franco-Prussian War of 1870-1871 illustrate this point. In Germany the death rate in 1869, the year before the war, was 28.5; in 1870, the first year of the war, 29; and in 1871, the culminating year of the war, 31. These figures include the armies in the field. For France, however, the defeated party, the figures were far different. In 1869 the death rate in France was 23.4; in 1870, 28.3; in 1871, 34.8. Thus, while Germany had its death rate increased by the Franco-Prussian War merely 2.5 per thousand of the population, France had its death rate increased 11.4. From this it is plain that it is the economic disturbances which accompany war, and particularly those which are manifest among the defeated, which cause a very large part of the higher death rate.
(2) As already implied, then, economic depression exercises a very considerable influence upon death rate, particularly when economic depression causes very high prices for the necessities of life and even widespread scarcity of food. This cause produces far more deaths in modern nations than war. The doubling of the price of bread in any civilized country would be a far greater calamity than a great war. While modern civilized peoples fear famine but little, there are many classes in the great industrial nations that live upon such a narrow margin of existence that the slightest increase in the cost of the necessities of life means practically the same as a famine to these classes. Statistics, therefore, of all modern countries, and particularly of all great cities, show an enormous increase in sickness and death among the poorer classes in times of economic depression.
(3) Climate and season are rather constant factors in the death rate of all communities. The rule here is that in northern countries the death rate is higher in winter, while in southern countries and in great cities the death rate is higher in summer. Taking 100 as an arbitrary standard, in Sweden in February deaths rise to 113, in August they go down to 79; while in Italy in February deaths are at 106 as compared with the standard, and in August at 111,—the period of minimum death rate in Italy being in the spring and autumn. In a great city like Berlin, if 100 be taken as the standard, deaths are 88 in February and 144 in August, owing very largely to the higher death rate of children in the summer months in great cities.
(4) The biological fact of sex also influences death rate. Males in general are shorter-lived than females. This is in part due to the fact that in human populations men are more exposed to the dangers of industry in earning a livelihood, while women are more secluded in the home. But this does not explain entirely the discrepancy in the death rate of the two sexes, for boy babies under the same conditions die more frequently than girl babies. As we have already seen, the female organism is the more stable, biologically, and hence females, while having less physical strength, have more vitality than males. In Great Britain the death rate (1872-1880) for the males was 22.7 per thousand of the male population annually, while the death rate for the females was 20.2 per thousand of their population annually.
(5) Conjugal condition is also a factor which affects death rate. The differences between the death rates of the married and unmarried have long been noted. The following table of the death rates of males and females of different conjugal classes between the ages of forty and fifty years (in Germany, 1876-1880), taken from Professor Mayo-Smith's Statistics and Sociology, illustrates this:
Single males ………………….. 26.5 per thousand
Married males …………………. 14.2 " "
Widowed males …………………. 29.9 " "
Single females ………………… 15.4 " "
Married females ……………….. 11.4 " "
Widows ……………………….. 13.4 " "
It will be seen from these figures that the death rate among the single is in all the more advanced years of life higher than among the married. The probable explanation of this, however, is not that the married state is better physiologically, as has been so often claimed, but that it is better socially. These figures are a testimony, in other words, to the social advantages of the home. Single persons, particularly in the more advanced years of life, who are without homes, are more liable to fall sick, and when sick are less liable to receive proper care. That these figures show the great social advantage of the home in preserving life is evident from the fact that among the widowed males, whose homes have been broken up, the death rate is higher even than among the single males. Moreover, in interpreting such statistics we must bear in mind that the unmarried in the higher ages of life are made up very often of those who are relatively abnormal, either physically or mentally, that is, of the biologically unfit. Inasmuch as the single persons include many of this class, and also lack the comforts of home, it is not surprising that the death rate is much higher among them.