Page:Popular Science Monthly Volume 60.djvu/436

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and contains one gram atom of gold in 1,360 liters, on the whole resembles colloidal platinum in its action, but it is remarkable that the same agents are not poisonous to both. Thus mercuric chloride, one of the strongest poisons for colloidal platinum, exerts an opposite influence on the catalyzing power of colloidal gold in alkaline solution.

Professor Gamgee's investigations into the magnetic qualities of the blood again touch physics on the one hand and physiology on the other. Starting from Faraday's observation that blood is a diamagnetic fluid in spite of the iron contained in its coloring matters, he has found that, while oxy-hæmoglobin is powerfully diamagnetic, the hæmatin and hæmin which may be obtained from it by the action of certain acids are strongly magnetic. He is extending his inquiries to the products obtained by the electrolysis of oxy-hæmoglobin. Mr. H. Swithinbank has been carrying out an elaborate investigation into the effects produced on tubercle bacillus by exposure to the cold of liquid air. He finds that prolonged exposure to that temperature, and even actual soaking in liquid air, has little or no effect on the vitality of the bacillus, though its virulence is to some extent modified. Length of exposure, indeed, does not seem to be an important factor, but what does produce a decided destructive effect on the vitality and virulence is exposure to alternations of temperature, as when the bacillus is frozen in liquid air, allowed to warm up to normal temperature, cooled again, and so on. The most striking incident at the Tuberculosis Congress held in London in July was the pronouncement by Professor Koch that bovine and human tuberculosis are distinct diseases, and that consumption is not transmissible from cattle to human beings. His views by no means commanded universal assent, and it was generally felt that more evidence was required before they could be accepted, and especially before any relaxation could be seriously contemplated in the sanitary regulations which have been framed on the assumption that the disease is so transmissible. During the proceedings of the Congress great stress was laid on the value of the open-air treatment of consumption, and as a result a strong impetus was given to the movement for establishing sanatoria where it can be carried out. One important semi-public institution of the kind was brought into use near Wokingham in the course of the year, and the erection of several others in various parts of the country has been determined upon. A sum of £200,000 placed at the disposal of the King by Sir Ernest Cassel has also been devoted by His Majesty to the erection of one of these sanatoria. Another mode of treating consumption, which did not receive nearly so much attention at the Congress, has been tried by Dr. Maguire, of the Brompton Consumption Hospital, with very promising results. This consists of the intravenous injection of formalin in carefully-graduated strengths and amounts. The effect, even in some very advanced cases, has been a rapid