Ueber das Problem der bösartigen Geschwülste—eine experimentelle und theoretische Untersuchung.

The author's working hypothesis that malignant tumors arise from an infectious origin was developed during forty years of surgical experience. During the past four years he has submitted it to an experimental analysis. About 2,400 white mice received injections of autolysates of certain closed carcinomas and sarcomas of human origin. The methods used in preparing the autolysates and making the injections are fully given. A 10 per cent suspension of fresh tumor substance in normal physiologic sodium chloride solution was also inoculated. Certain of the mice likewise were inoculated with tumors of animal origin. About 6 or 7 per cent of the inoculated mice developed neoplasms, which were studied.

The extensive experimental work is carefully and rather completely presented. It is splendidly illustrated; the numerous figures themselves are a real contribution to the study of cancer.

There cannot be any doubt that the tumors are real neoplasms. Heidenhain concludes that