Kapronczay Károly szerk.: Orvostörténeti közlemények 230-233. (Budapest, 2015)
KÖZLEMÉNYEK - Elek Gábor—Müller Miklós: Bauer Ervin és a rákkutatás
96 Comm, de Hist. Artis Med. 230-233 (2015) Bauer’s cancer theory soon received positive acclaim among experimental oncologists. His paper {Bauer 1923a) was quoted in clinical journals (Tobler 1924). Extracts of homologous tissue were shown to have higher surface tension than those from cancerous tissues {Kagan 1924a). Transplants of mouse ascites tumours treated with surface-active agents took with a higher percentage {Kagan 1924b). Parallelism was noted between malignancy of a tumour and decrease of surface tension of extracts of the tumours {Solowiew 1924). Serum exhibited lower surface tension in pregnancy, too {Solowiew 1925). Decrease of surface tension was claimed to occur in mouse cancer elicited with carcinogens {Deelman 1924). Decrease of surface tension could also lead to permeability changes in the membrane of tumour cells {Traube 1929). What was behind this fast acceptance of the idea? First of all, the theory was amenable to experimental testing - and as seen on Table B - it could bring together and easily explain almost all of observed facts of malignant growth. Early theories based on morphology could explain only partial aspects of the cancer problem. The wast array of facts obtained in clinical and experimental studies needed more than a morphological theory. Bauer’s theory - while it was short lived - was the most comprehensive cancer theory from the colloid chemical point of view. Even more so, his principle formulated the essence of pathology of his time (Table A, row 2). A living organism not in equilibrium, but able to perform work, always counteracts damaging external changes and restores its non-equilibrium state. This is the regulatory activity {Bauer 1920 13-14). ‘ We call disease all life processes that are not regulatory, where the energy taken up is not or not fully used up for the increase of non-equilibrium. This means that disease can only be elicited by external influences {Bauer 1920 59-60, see Elek- Müller 2006). This is at the same time the essence of his humoral, colloid pathology. We can now understand the above quoted sentence by Bauer: ‘Based on my experiments, facts and considerations, I regard the problem of cancer solved. The surface tension of the serum provides us a measurable parameter, from the value of which the origin and growth potential of cancer depends' {Bauer 1923a 374). Critique and afterlife of Bauer s theory Bauer’s paper {Bauer 1923a) led to a series of follow-up studies. Together with the already referred papers more than a dozen communications were published on the surface tension of sera from cancer bearing organisms and of their organs. The size of the samples was often small, the values obtained for control sera were occasionally wrong, different authors employed different methods (see Heréik 1934 150-152). Research in the 1920s did not include yet statistical evaluation of results, calculation of errors, numerical expression of the confidence limits. Even without such evaluations Bauer’s hypothesis, seeing the common cause of cancer formation in lowered surface tension of the serum was regarded premature, not considered carefully. While differences in surface tension of various tissue extracts were clearly documented, it became clear that establishment of experimental tumours leads to fluctuations of surface tension not only in the serum but also in tissues surrounding the tumour. These changes attain their maximum at different time points depending on the type of tumour and the surrounding tissue (see Heréik 1934 152- 157). Differences in surface tension of different organs do not give a complete explanation of
