100 YEARS AGO

The similarity between malignant disease and tuberculosis has led numerous investigators to seek for an organism which would bear the same causative relation to cancer as the tubercle bacillus does to tuberculosis... The main point of difference between the adherents of the parasitic theory of the origin of cancer and their opponents centres upon the significance of certain undoubted microscopic appearances, chiefly of the growing portions, of cancerous growths. Some observers maintain that these microscopical appearances represent an organism of a protozoic type, others regard them as due to degeneration of the cancer cells. The majority, however, of microscopists do not regard the presence of a parasite in cancerous growths as proved. In the case of sarcomata, the parasite is supposed to be, not of animal, but of vegetable origin... If we turn from the study of the hypothetical cancer parasite to a consideration of the influence of general climatic conditions upon the incidence of cancer, we shall be treading upon more certain ground. The existence of so-called “cancer houses” seems to rest upon very strong evidence.

From Nature 20 March 1902.

50 YEARS AGO

Sir Lawrence Bragg delivered the thirty-sixth (1952) Guthrie Lecture of the Physical Society on March 12, when he discussed “X-ray Analysis of Proteins”. Sir Lawrence said that the attempt to discover the atomic arrangement in the protein molecule seems very ambitious. Ever since Bernal first showed that crystals of protein give X-ray diffraction pictures, it has been clear that a protein molecule of a given type is a structure with a definite individual form; the X-ray diffraction spots are very sharp and reproducible and extend to regions corresponding to interatomic distances. The molecules are, however, of great complexity. It has been a triumph of X-ray analysis to pass from simple substances like rock-salt to such molecules as strychnine or penicillin with about one hundred atoms. Attempts are now being made to analyse a molecule such as haemoglobin, which contains fifteen thousand atoms. The reward, if an analysis were completed, would be great, because the determination of any one protein would undoubtedly cast a flood of light on the character of these bodies, which Nature has selected as the basis of living matter.

From Nature 22 March 1952.