deaths in the female sex are due to cancer (Hoffman). From the thirty-fifth year on the death rate from cancer increases rapidly. There seems to be an optimal age for the appearance of certain cancers which differs somewhat in various kinds of cancer. Whether the death rate from cancer as a whole increases with advancing age or whether there occurs a maximal death rate at a certain age after which there is again a decrease observed does not appear to be certain.
While the typical cancers which we have considered so far occur in the large majority of cases in older people, some cancers of the same type may appear in young people; thus carcinoma of the stomach, tongue, esophagus, appeared in very rare cases in children. But there are special kinds of cancer which appear typically in younger persons. This applies for instance to the "carcinoid" tumor of the appendix and to similar often multiple carcinomata of the small intestines, which are found in relatively young adults (Bunting). These tumors are much more benign than the typical carcinomata—they grow very slowly and make ordinarily no metastases. But certain tumors are quite typical for young children. While in adults carcinomata are considerably more frequent than sarcomata, in children sarcomata are much more numerous than carcinomata. The most frequent seats of cancer in children are neither the gastro-intestinal tract nor the female generative organs, but kidney and adrenal, next the eye, brain, skin, cranium and liver. And while the few carcinomata of the stomach and intestines in childhood are observed in 12-14 year old children, the tumors of the kidney appear often in infants.
Besides the sarcomata we find in young children frequently so-called mixed tumors, consisting of several kinds of tissue; in the kidney tumors for instance we may find side by side proliferating epithelial gland tissue, round cells resembling sarcoma, muscle and even bonelike tissue. In other organs also we find not rarely such mixed tumors to prevail among the cancers in children. Cancer of the female generative organs occurs in children not mainly in the uterus, as is the case in adults, but in the ovaries and in the vagina. In the eye and brain we find besides sarcomata which originate from connective tissue cells certain special kinds of structures, the so-called glia cells—which are related to nerve cells—to give origin to malignant tumors. Even in the abdominal organs there may appear in young persons tumor-like proliferations of cells derived from the sympathetic nervous system (Neuroblastoma of J. H. Wright).
There is still another class of tumors which occur especially in children and in young adults, but may occasionally be observed even in older people and which are of great interest, the so-called teratomata or embryomata. They have certain seats of predilection, as for instance in the pelvis in front of the sacral bone, or in the anterior mediastinum,
