can be made with any hope of accuracy. It is then apparent that the energy of assimilation of transplantable tumours is very variable, so that some strains surpass others enormously in this respect. At the same time different series of the same strain may show great differences. Further, as Apolant has pointed out recently, the adaptability of a tumour, which is usually measured by the percentage of success on inoculation, is to a high degree independent of the energy of growth, and he instances tumours which grow in nearly 100 per cent. of normal animals with great slowness. Tumours which grow extremely slowly in high percentage of normal animals seem to show that in them the essential phenomenon is a condition of unstable metabolic equilibrium rather than of increased energy of assimilation, and that the latter property when present is of subsidiary importance. We possess such a carcinomatous strain, placed at our disposal by Mr. F. W. Twort of the London Hospital, and our squamous-cell carcinoma (32) is an example of the converse condition in which a tumour with great energy of growth seldom shows a maximal percentage of success.

The existence of such tumours, the biological characters of which are retained through long periods of propagation, shows that the cellular transformation which initiates carcinomatous growth may take place in varying degrees. The impress which the cells receive at this time, while permitting of great histological variations in their descendants, colours permanently their whole biological behaviour. This biological alteration is of such a kind that the cells are able to take up nourishment, increase in size and multiply indefinitely. They acquire an individuality, and powers of resistance to injurious agencies, superior to those of normal tissue elements. They retain, with probably only apparent exceptions, the chemical equivalent of the histological characters of the elements from which they arise and exhibit a corresponding tendency to an organoid arrangement, in every situation in which they can grow.

LITERATURE.

ALBRECHT, E.-Die Grundprobleme der Geschwulstlehre. Frankfurter Zeitschrift für Pathologie, 1907.

ALBRECHT, E.-Randbemerkungen zur Geschwulstlehre. Ibid.

APOLANT, H.-Die Epithelialen Geschwülste der Maus. Arbeiten aus dem Königlichen
Institut für Experimentelle Therapie, Frankfurt a/M. 1906.
BORREL, A.-Epithélioses infectienses et Epithéliomas.

Pasteur, 1903.

Annales de l'Institut

BORREL, A.-Le problème du Cancer. Bulletin de l'Institut Pasteur, 1907.

V. DUNGERN, E., & WERNER, R.-Das Wesen der bösartigen Geschwülste. Leipzig,

1907.

I

EBERTH & SPUDE.-Ueber familiäre Endotheliome Virchows Archiv, 1898.

EHRLICH, P.-Experimentelle Karzmomstudien au Mäusen. Zeitschrift für Aertzliche

Fortbildung, 1906.

EHRLICH, P.-Ueber ein transplantables Chondrom der Maus.

Arbeiten aus dem

Königilichen Institut für Experimentelle Therapie. Frankfurt a/M., 1906. FLEXNER, S., & JOBLING, J. W.-Infiltrating and Metastasising Sarcoma of the Rat. Journal of American Medical Association, vol. 48, 1907.

GIERKE, E.—Die hæmorrhagischen Mäusetumoren. Ziegler's Beiträge, 1908. HAALAND, M.-Ein Chondrosarkom der Maus. Zeitschrift für Krebsforschung,

Bd. 5, 1907.

HAALAND, M.-Les Tumeurs de la Souris. Annales de l'Institut Pasteur, 1905. HAALAND, M.--Musekraeft og experimentel Kraeftforskning. Norsk Magazin for laegevidenskaben, 1907.

HANAU. Erfolgreiche experimentelle Uebertragung von Carcinom. Fortschritte der Medizin, Bd. 7, 1889.

V. HANSEMANN, D.-Kritische Betrachtungen zur Geschwulstlehre. Zeitschrift für
Krebsforschung, Bd. 3, 1905.

HENKE, F.—Mikroskopische Geschwulstdiagnostik Gustav Fischer. Jena, 1906.
HERTWIG, O. & POLL, H.-Zur Biologie der Mäusetumoren. Abhandlungen der
Königlichen preussischen Akademie der Wissenschaften, 1907.
JENNY.-Beiträge zur Lehre vom Carcinom. Archiv für Klinische Chirurgie, Bd. 51,
1896.

JENSEN, C. O.-Experimentelle Untersuchungen ueber Krebs bei mäusen. Centralblatt für Bakteriologie, 1903.

JENSEN, C. O.-Nogle forsøg med Kraeftsvulster. Hospitalstidende, 1902. LAZARUS-BARLOW, W. S.-The relations of Endothelioma to other forms of new growth. Proceedings of the Royal Society of Medicine, 1908.

LEWIN, C.-Experimentelle Beiträge zur Morphologie und Biologie bösartiger Geschwülste bei Ratten und Mäusen. Zeitschrift für Krebsforschung, Bd. 6, 1908. LIVINGOOD, L. E.-Tumours in the Mouse. Johns Hopkins Hospital Bulletin, 1896. LOEB, L.—On Transplantation of Tumours. Journal of Medical Research, 1901. LOEB, L.-Further Investigations in Transplantation of Tumours. Ibid., 1902. MICHAELIS, L.-Experimentelle Untersuchungen über den Krebs der Mäuse.

Medizinische Klinik, 1905.

MICHAELIS, L.-Ueber den Krebs der Mause. I. Zeitschrift für Krebsforschung, Bd. 4, Heft 1,

MICHAELIS, L.-Idem. II. Ibid., Bd. 4, Heft 3, 1906.

MICHAELIS, L.-Ein transplantables Rattencarcinom.

forschung, Bd. 5, 1907.

Zeitschrift für Krebs

MORAU, H.-Sur la transmissibilité de certains néoplasmes Archives de Medicine expérimentales. 1894.

TWORT, F. W.-Demonstration before Pathological Society of London. 1906. TYZZER, E. E.—A Series f Twenty Spontaneous Tumours in Mice. Fourth Report of the Caroline Brewer Croft Fund Cancer Commission. Boston, 1907.

A complete Bibliography of papers from the Laboratory of the Imperial Cancer Research Fund is given as an Appendix to this Report.]

THE HÆMORRHAGIC MAMMARY TUMOURS OF MICE*, WITH RESULTS OF RESEARCH INTO SUSCEPTIBILITY AND RESISTANCE ΤΟ IN OCULATION.

BY DR. EDGAR GIERKE,

Privatdozent, and Assistant in charge of the Department of Pathological Histology in the Pathological Institute of the University of Berlin.

THE epithelial tumours of mice have been classified by Apolant, whose classification has been generally adopted. But, although Apolant himself emphasises the fact that individual forms cannot be differentiated sharply, and that an alveolar carcinoma may again assume an adenomatous formation under certain circumstances, as he states in his latest paper, it seems practical to distinguish several groups which, although they retain during transplantation certain structural characteristics as a rule, at the same time present variations from a biological point of view. The majority of epithelial tumours in mice, so far as we are not dealing with squamous-cell carcinoma, may be regarded, according to Bashford and Murray, Apolant, Borrel and Haaland, as mammary tumours. Among these Apolant distinguishes :(1) Adenoma-(a) adenoma simplex; () cystadenoma simplex ; (c) adenoma cysticum oedematosum sive hæmorrhagicum; (d) cystadenoma papilliferum: (2) Carcinoma—(a) carcinoma simplex alveolare; (b) cystocarcinoma hæmorrhagicum; (c) carcinoma papillare; (d) fissure-forming adenocarcinoma.

The alveolar, fissure-forming, and papillary carcinomata have been successfully propagated through many generations by a number of investigators. The hæmorrhagic carcinomata, on the contrary, could, at the first beginnings of experimental study in mice, not be transplanted at all, and later only in a few cases were they transplanted with any success, so that Ehrlich estimates the yield of the inoculations as not higher than per cent. But a special interest

*My stay in London being limited, my experiments terminated in September 1907. Thus many of the questions raised can only be definitely settled after a continuance of the enquiry.