It will now be our province to investigate whether it is to age solely that the predisposition to cancer is to be attributed, and this may seem at the first glance to be a valid conclusion when it is remembered that the same prevalence is observed in the male sex between the ages of forty and sixty (compare Picot, I. c., p. 1184), or whether it is the menopause which exercises this influence. Not wishing to enter more fully just now into the etiology of carcinomatous disease in general, I will only point out that the influence of advanced age in general has been explained on the hypothesis of a diminished power of resistance of the various tissues.
Now, while it will have been recognized from the above remarks that age undoubtedly plays an important role in the etiology of carcinoma uteri, it will be shown that the second factor, namely heredity, does not possess an importance to the extent that has been assigned to it. Al though authentic observations are not wanting to show the influence ex erted by a hereditary taint upon the development of cancer of various organs, yet the number of such observations, as far as concerns carcinoma of the uterus, is by no means so large as has been generally supposed. Whether this depends upon the nature of epithelioma of the uterus, that is, its more localized development and corresponding course, or whether it is due to imperfect observation, must remain undecided. At all events it is certain that most investigations have been very deficient in this direction, on the one band because the necessary researches have not been sufficiently painstaking, and on the other hand because these investiga tions, even when conducted on a large scale, as is possible in hospitals, so often yield only meagre results from the ignorance of the ordinary hos pital patients regarding the medical histories of their parents and relatives. We can only expect to derive information on this point from the records of private practice, among the more cultivated and intelligent classes.
Out of 1203 cases of this description (published by Tanner, Lever, Lebert, Scanzoni, L. Meyer, Sibley, Barker, Winckel and myself) there were but 90 or 7.8 per cent. in which it was stated that cancer had oc curred among the more immediate relatives of the patients. Picot found an inherited predisposition in 13 per cent. of 978 cases of carcinoma of
various organs collected by himself. According to these figures, heredi tary taint would seem to possess less significance in the etiology of uterine cancer than in the same disease affecting'other organs of the body.
Other factors, to which etiological importance has sometimes been attached, such as the constitution, the temperament, the occupation, etc., of the individual, deserve only passing mention here, as neither my own experience nor the literature of the subject furnishes anything more than mere conjecture in this regard. The same is true of the etiological significance of previously existing disease. E. Martin's' assertion that infectious diseases of the genital organs transmitted by intercourse from husband to wife excite a predisposition to the development of epithelioma of the uterus, must be regarded, for the present, as entirely without foun dation, not even an attempt having been made to substantiate it by facts.
Diverse local affections of the cervix uteri seem to be of greater signifi cance as predisposing agents to cancerous degeneration. Persistent catarrh of the cervical mucous membrane, with the formation of erosions, has long been regarded as a precursor of malignant disease. Many have called attention to the fact that there is but a short step, anatomically speaking, between a papillary erosion and a true papilloma on the one hand, and between a papilloma and an epithelioma on the other. In fact the latter transformation has been shown to have taken place.
More recently Ruge and Veit have shown that a causal relation exists between certain types of so-called erosions and ectropionic changes of the os uteri, and a neoplastic development of gland tissue, and they have also pointed out that these conditions were to be regarded as the forerunners of epithelioma.
Breisky 2 has also published some observations tending to show that eversion of the mucous membrane of the cervix uteri, after lacer ation of the os (cicatricial ectropium of Emmet), may, in consequence of the long-continued irritation to which it is necessarily subjected, be come the starting-point of a cancerous growth. Now while this and similar observations are most valuable, from a therapeutic aspect, they throw but an obscure light upon the etiology of these processes.