THE effects of roentgen rays on several kinds of chemical compounds in solution have been studied by different investigators. As a rule, it has not been determined exactly what kind of reactions were produced, but definite changes took place in most of the compounds reported upon. The quantitative relations between the dose and the change produced can be classed in four different groups: (1) no measurable (or appreciable) effect; (2) the change follows the mass action law; (3) the change is directly proportional to the dose given, and (4) no simple relation between the dose and the change is found. To the first group belong solutions of cholesterol in benzene (1); to the second group, trypsin (2) and hemoglobin (3) in weak aqueous solutions; to the third group, aqueous solutions of ferrosulphate with some sulphuric acid (4), and to the fourth group, solutions of cholesterol in chloroform (5). In order to find out more about the laws governing the reactions that take place when chemical compounds are exposed to roentgen rays, we have started a series of experiments in our laboratories. For these experiments we utilize the radiation from a water-cooled high voltage Coolidge tube while patients are being treated. The solutions and gases used, so far, have been sealed in glass tubes and these placed inside the “Acme International” tube stand in which the roentgen-ray tube is installed. The distance from the target to the center of the tubes was 57 cm.; 180 to 200 K.V. and 30 ma. were used. The solutions were sealed in glass tubes about 15 cm. long and 1.5 cm. in diameter, with a content of about 15 c.c. of the solution. Usually two tubes were placed together; one inside a lead container with 3 mm. thick wall which prevented any appreciable amount of radiation from reaching the solution used as control, and the other inside an aluminum container of 0.3 mm. wall. Thus only a small amount of the roentgen radiation was stopped by the aluminum, while visible radiation was excluded and the temperature kept equal to that of the other tube. The filter consisted only of this aluminum and the glass wall which was about 1.5 mm. thick. Anne Lohmann co-operated in the experiments with the solutions. They will be reported in more detail elsewhere (6). In order to find out to what dose the solution was exposed on an average per hour, we radiated 0.001 molar ferrosulphate in a 0.8 N sulphuric acid solution. According to Fricke and Morse (4), 50 per cent of the ferrosulphate in such a solution is oxidized to ferrisulphate by a dose of 28.35 k.r. (kilo roentgen). Table I gives the results obtained when the solution was irradiated with different amounts of roentgen rays. The values obtained indicate that less was oxidized per hour the longer the solution was exposed (Column 3, Table I). The measurements are, however, too few and the experimental errors too large to permit a definite conclusion, especially as the measurements were made on different days.
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Wilhelm Stenström (1929) studied this question.