In the centre of carcinomata which have undergone degeneration the fluid, the so-called cancer-milk of the older writers, consists practically of a pure culture of these organisms. The fluid from malignant ovarian cysts likewise contains a large number of the organ isms, and the peculiarly characteristic mush found in the cavities of certain adenocarcinomata of the ovaries is like wise largely composed of the various forms of the parasite. This shows that bodies identical in appearance to those found in the peritoneal fluid of the first ease mentioned can be found in all scrapings of cancer. The small, highly refractive form which in suspension possesses a characteristic oscillating mo tion, the larger pale forms projecting pseudopodia, and the saceular forms containing highly-refractive spherical holies could be detected with equal facility in the fresh scrapings of any malignant tumor. II. R. Gaylord (Amer. Jour. Med. Sri., May, 1901).
The parasitic theory of the etiology of carcinoma cannot stand. It cau—as yet, at any rate—be brought into relation with only one group of malignant tumors. The infectious pathogenic agents produce reactive inflammatory conditions, while in carcinoma the meta s tases are produced by tumo•-cells that cause no reaction of infection in the sur rounding tissues. It is extremely diffi cult to explain how the parasites could reach the region in which carcinoma arises, except in those instances in which it is situated at points directly accessible to the exterior. If parasites cause the disease, one would expect carcinoma of the breast to be practically always situ ated near or on the surface; but this very often is not the case. As to the parasites described by a large number of investigators recently, and variously con sidered to be protozoa and blastomycetes, reference is made to N6sshe's work, which demonstrates that they are cell inclusions of another nature. The only satisfactory conclusion that can be reached is that the malignancy of certain tumors is explainable only upon the basis of the production of toxic substances in the life-activity of the cells, which pro duce alterations in the cells that inter fere with their normal metabolism and with their normal structure. This change in the cells may be very different in grade and in quality. The resistance of the normal organism to the unchecked growth of its elements might be ex plained through the fact that normally the specific substances which favor their growth—or which damage surrounding tissues, and thus give them opportunity for growth—are neutralized. In the ease
of malignant tumors, these sub stances are not neutralized. Marchand (Deutsche med. Wochen.. Oct. 2, 19021.
It is claimed by investigators who be lieve that cancer is due to parasites: 1. That a proliferation of the epithelial cells analogous to cancer can be produced by certain protozoa (nodules due to con cidium oviforme). 2. That certain skin lesions characterized by epithelial-cell proliferation are due to the action of a so-called protozoan, molluscum contagi osum. 3. That blastomycetes constantly are present in human cancers and are the cause of the lesion. 4. That, by ex perimental inoculations of animals with blastomycetes, true epithelial or cancer ous nodules can be produced. 5. Finally, that the well-known endoccllular bodies seen in the protoplasm of cancer-cells have a definite morphology, are para sites, and cause cancer. It was the ob ject of investigators whose work is here reported to study each of these questions.
General conclusions: As a result of investigation it is concluded that: 1. The lesion produced by coccidium ovi forme is essentially a chronic inflamma tion not analogous to cancer. 2. The lesions in molluscum contagiosum show certain changes in the epidermis not due to the action of protozoa and not analo gous to cancer. 3. The so-called "blas tomycetes" of Sanfelice and Plimmer are toruhe. 4. The lesions produced by these toruhe are essentially nodules of peculiar granulation tissue, not cancerous or in any sense "tumors." 5. Blastomycetes are not constantly present in human can cers. 6. The cancer bodies are not para sites or the cause of the lesions, but are probably atypical stages of the process of secretion by glandular epithelium. Re port of the Men Working under the Can cer Commission of Harvard University for the Year 1901-1902 (Amer. Jour. Sciences, ,June, The frequency of cancer in the vari ous parts of the body varies in different countries, and two observers in the same city often arrive at different conclusions.
In my experience, cancers of the stomach and of the breast have been about equal in number, but were collected in entirely different ways, the first while making over 2000 autopsies and the latter being received by me for microscopical study. In 1266 cases of cancer (and epithelio mata) collected by Munn for the records of the Middlesex Hospital, 426 were of the uterus and 417 of the breast. In France 'cancer of the stomach seems to head the list in point of frequency.