OLD AND NEW THEORIES AS TO TUMOR FORMATION, IN THEIR APPLICATION TO THE MAMMA.
That tumors are parasites on the body and not connected with it by means of the blood and lymph streams, no one has believed for a long time; but that they originated from black gall, blood and malignant humors, which occasionally found a resting-place in the mamma, and then became connected with the circulation of the body, is an opinion that was generally disseminated until the middle of this century. As it was agreed in regard to their developmental history that all organs originated from a primarily unformed blastema, from which the cells are first formed, so, at the time when John Muller had already discovered that they originated from the same or similar tissue as the tissue of embryos, it was agreed that tumors grew from an unformed protoplasm, which was either blood or lymph, or excreted by blood or lymph vessels; that it.; to say, this juice contained the vital agents, though not always their corpuscular ele ments. The proposition " omnis cellula ex cellulo " was first promulgated by Remak for the developmental history; he first used it in regard to the origin of carcinoma, and this idea was afterwards employed by Vir chow to include all pathological neoplasms and with great consistency in all new researches. To-day no one believes in the origin of tissue from amorphous protoplasm, at least as regards the human organism. Still, as certainly and as systematically as we can now follow up the origin and further development of the most complicated tumors, there is one thing which remained obscure and is so to-day, namely, the reason of the ori gin and the typical further development not only for the individual forms of neoplasms in the narrow sense, but also for the so-called inflammatory neoplasms. Clinical observation leads always and again to the thousand fold observed fact, that after the irritations known to us, which may act accidentally on the tissue or be used exclusively for the purpose of ex periment, and which we designate as " inflammatory," again do the same series of phenomena arise and run their course typically. And just here
there is great difficulty with regard to chronic inflammations, which we can only imitate experimentally when we apply the irritation for a long time, or when we use substances which are very finely divided and main tain the irritation, because they are not absorbed and excreted (tuberculous experiments). It is not yet possible to produce true tumors experimen tally, and we therefore conclude that we do not know the specific forms of irritation which lead to tumor formation, or that we do not know the condition in which the tissues must be when tumors can be developed from ordinary known causes. Virchow, in his endeavor to explain the existence and growth of tumors, without the aid of unknown and more or less mystical factors, but only with the aid of known observations, or at least to bring them nearer explanation, clung to the opinion that one of the known must cause the origin of tumors, and for this reason used everything which could, from that point of view, throw a ray of light on this dark territory. It has now become correct to say that a blow, pres sure, a fall is with great certainty the cause of the origin of tumors in many cases; that carcinomatous ulcers are proved to originate from scars and chronic sluggish ulcers; that the influence of wind and weather, and perhaps the irritation of the skin of the face by shaving, etc., especially favor the development of carcinomas of the face. As regards these pre disposing factors in their application to the breasts, they have been so carefully discussed and proved by statistics by Al. von Winiwarter, that I must refer all, who are interested in this matter of etiology, to his book.
lie can only adduce l2 cases out of 170 (7.06 per cent.) of mechanical injuries (blows) acting at once, in which the declarations of the patients were sufficiently definite to induce belief; he states, however, that even these few cases give but little etiological support, since the carcinoma either made its appearance immediately after the blow, or after a long time, without the appearance of the phenomena of contusion and chronic irritation.