As early as 1923 it was shown by Maisin (1) that cancer is a constitutional as well as a local disease, an observation that has been developed and confirmed by Mertens (2), Masse (3), Fischer-Wasels and Büngeler (4), Kreyberg (5) and Beck (6). Many experiments have since been undertaken in the hope of influencing the responsible factor or of identifying the fundamental metabolic disturbance. In 1930 Pourbaix (7) demonstrated the presence of a real disorder in fat metabolism in cancerous and precancerous conditions.
For the past seven years we have been seeking to find in normal organs some substance which will inhibit cancer growth. In our earliest experiments (1928) we tested the influence of a liver diet on tar cancer in mice (8, 9, 10, 11). Encouraged by our results, we then undertook more extensive studies on the effect of other tissues on tar cancer. The details of the experiments with liver, thymus, and muscle were published by one of our assistants, François (12), in 1931. Studies were also made of spleen, bone marrow, and brain. Of these, brain proved to be of special interest, as exerting a decided inhibiting effect on tumor growth. Attempts were then made to isolate the growth-inhibiting factor. The details of these experiments were not published, being reserved for later publication in the thesis of our assistant, Ronsse,1 but the preliminary results were reported at the Société de Biologie in 1931 (13–15), and in the following year the technic for extracting the antiblastic substance from brain and other tissue was described (16). Further accounts of the work appeared in 1932 and 1933 (17, 18), and in the latter year results of analyses made to ascertain the chemical composition of the extracts were published (19). A brief report of the work was also presented at the International Cancer Congress at Madrid in 1933 (20). Since that time growth-inhibiting substances have been extracted from the suprarenals and the hypophysis by the same methods as were previously used for brain and other tissue (16). Reports of this work have been made by Vassiliadis (21, 22).