Use of Bismuth.—In 1901 Becker gave small doses of the same material and was the first to publish anything definite about the radiology of the alimentary tract. His results were confirmed in the same year by other workers, but the danger of poisoning (chiefly from metallic impurities in the bismuth) was so great that not sufficient could be given for diagnostic purposes, and nothing of any special value resulted. Somewhat later, the pub lication of a paper on the treatment of gastric catarrh by large doses of bismuth inspired Rieder, of Munich, to give large doses of bismuth in order to examine the stomach and intestines by means of X-rays.
Some few cases of poisoning were later reported, but with the help of the chemist an absolutely non-toxic preparation of bismuth carbonate came into use. The production of this non-toxic prep aration of bismuth was difficult and it never attained to universal popularity. In 1910 experiments were made with barium sulphate —which was found to be almost as opaque as bismuth and not only much more readily freed from inorganic impurities but infinitely cheaper to use. With very few exceptions radiologists use some form of this salt in diagnoses.
The Gastrointestinal Tract.—The production of a safe and suitable method of making the gastro-intestinal tract opaque very greatly stimulated the investigations which were being carried on as to the condition of the alimentary tract in health and in disease. The study of both is still far from complete but, even with the results so far attained, diagnosis of intra-abdominal conditions has been greatly improved and numerous complaints previously de scribed as "indigestion" and "gastritis," for example, are now readily classified.
Cancer and Gastric Ulcers.—Cancer of the stomach gave fairly typical X-ray evidence, but gastric ulcer proved almost as elusive to the radiologist as to the clinician. Certain investigators had observed a "niche" or recess on the wall of the stomach but its significance was not appreciated. In the same year (1910), Haudek and others, but chiefly the former, produced definite evidence that the "niche" was in reality an ulcer on the gastric wall filled with barium. Since then many other signs indicative of gastric ulcer have been noted and now the diagnosis of this condition is not a difficult matter. Thanks to the labours of Carman, Miller, Gregory Cole and Barclay, the duodenum is becoming an open book to the radiologist particularly in respect of ulceration.
covery of X-rays, they were known to have certain curative properties, and scientists all over the world have been experi menting to place this form of treatment on a sound and scientific basis. Intractable skin diseases (q.v.) which resisted every other remedy often responded to X-rays, and it was noticed that some forms of malignant disease disappeared after treatment by irradi ation. Means of accurately measuring the dosage of the rays were not known, but cancer had become so terrible a scourge that they were utilised indiscriminately for its relief, and at times with disastrous results. From 1905 onwards methods of measurement improved and in 1914 a dose could be administered with a certain amount of accuracy, the risk of burning became almost negligible, and we are now in possession of instruments capable of giving precise knowledge as to the amount of X-rays falling upon a given area. A spectroscope is used which takes a photograph of the X-ray spectrum. From it the wave-length can be ascertained and the shorter the wave-length the more penetrating the X-ray.
Most of this work was carried on in Germany, where the idea prevailed that it was only necessary to get an intense enough ray and to measure it carefully in order to kill cancer. Apparatus for the production of these very intense rays was soon devised and before very long a great number of patients were undergoing treatment, so rapidly did this idea stimulate the popular imagina tion. In the early stages of this new form of X-ray therapy the results appeared to be most encouraging and the conquest of cancer was thought to be within reach. Subsequent statistics showed relief to be merely temporary. Great credit is, however, due to the early German workers and other pioneer specialists for the ingenuity and skill shown in standardizing and ren dering accurate the dosage of X-rays ; but as a method of treatment of cancer we are getting no better results than were obtained in 1910. Russ and Colwell (Radium, X-Rays and the Living Cell) put the matter thus : "In radiology applied to biological problems there is a double difficulty, for the intensity of the radiation used, whether it be X-rays or Radium is a quantity which under many experimental conditions presents very considerable difficulties in its accuracy of measurement, and the animal itself provides a complex which refuses to be reduced to simple terms." See X-RAYS; RADIOLOGY ; X-RAY TREATMENT.