some countries it is slightly more prevalent among men. On the average 35-45 per cent, of all cancer affects the stomach and about 22 per cent, of all cancers develop in the female generative organs and breast. About 20-35 per cent, of all women who die from cancer have cancer of the uterus. Cancer occurs also relatively frequently at the lip, tongue, rectum and skin, especially of the face. Sarcoma is much less frequent than carcinoma. The relative frequency of the different varieties of cancer in the most populous areas of the United States is (according to S. C. Dixon) as follows: mouth 3.2 per cent., stomach and liver 38 per cent., intestines 11.7 per cent., female generative organs 14.3 per cent., breast 8.5 per cent., skin 3.7 per cent.
There occur, however, some notable deviations from the average rate of the different varieties in some countries. In Norway cancer of the uterus is relatively rare; only 6.3 per cent, of cancer develop in the uterus and 3.8 per cent, in the breast. In some parts of Norway cancer of the uterus is almost unknown. Cancer of the gastro-intestinal tract preponderates therefore considerably in Norway. In Sweden on the other hand cancer of the uterus is only slightly less frequent than elsewhere. In Switzerland also cancer of the stomach preponderates somewhat more than in the majority of other countries. A very peculiar deviation we find furthermore in Portugal, where cancer of the lip is very much more frequent than elsewhere (29 per cent, in men). While, on the whole, carcinoma of the male generative organs is rare (0.4 per cent, of all kinds in man), it is very frequent in the Cape Verde Islands. The proportion of cancer of the respiratory and excretory organs (kidney, ureter, bladder) is everywhere relatively low.
If we compare the incidence of cancer in the two sexes we find in most countries women somewhat more frequently affected than men. In Prussia the proportion is 3 men to 4 women. The relative incidence in women is even somewhat greater in the United States. The difference depends upon the difference with which various kinds of cancer affect the two sexes, and mainly upon the frequency of cancer in the female generative organs and breast; cancer of the gall-bladder, intestines, especially rectum, is also more frequent in women than in men, while cancer of the lip, tongue, skin, is more frequent in men. Cancer of the stomach is either equally frequent in both sexes or somewhat more frequent in men. In countries where cancer of the stomach prevails, and where a larger proportion of men than women are affected by this kind of cancer, the cancer death rate is higher in men, as in Switzerland, Norway and Kyoto (Japan).
There is no marked difference between married and single persons; the majority of statistical studies, however, indicate that married women are more frequently affected by cancer of the uterus and breast than unmarried women.
