The frequency of carcinoma of the stomach may be estimated either from data supplied by a large series of necropsies, from a study of the bills of mortality of different countries, or from the clinical statistics of various great hospitals. Each of these sources of information, however, presents so many chances of error that the results obtained from them must be regarded as strictly relative in their value. Necropsies are obviously the most reliable, in so far as the actual existence of the disease is concerned; but since only a certain proportion of hospital patients are examined after death, post-mortem records are apt to contain an excess of obscure or interesting cases, and consequently to exaggerate the frequency of all varieties of abdominal disease. Bills of mortality, although theoretically perfect from the fact, that they represent all causes of death among all classes of the community, are based almost entirely upon the unverified diagnoses of a vast number of medical practitioners of varying knowledge and experience, and are therefore always open to grave suspicion.1 Finally, clinical statistics from the hospitals of London, while they undoubtedly represent an excellent average of diagnosis, are concerned entirely with the poorer classes of an urban population, and consequently lack the most essential feature of the statistics of mortality.
1 In this connection it may be mentioned that out of fifty-six cases admitted under our care into hospitals with a diagnosis of cancer of the stomach, thirty-one, or 55.3 per cent., were proved to be suffering from that complaint, while the remaining 44 7 per cent., were free from the disease. The average duration of the illness at the time of admission was nearly four months.