(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 " "