428 POPULAR SCIENCE MONTHLY. 



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-hsemoglobin is powerfully diamagnetic, the hsematin and 

 hgemin 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-hsemoglobin. Mr. H. Swithinbank 

 has been carrying out an elaborate investigation into the effects pro- 

 duced 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 Lon- 

 don 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 evi- 

 dence was required before they could be accepted, and especially before 

 any relaxation could be seriously contemplated in the sanitary regula- 

 tions 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 sana- 

 toria where it can be carried out. One important semi-public institu- 

 tion 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 coun- 

 try has been determined upon. A sum of £200,000 placed at the dis- 

 posal 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 Consump- 

 tion Hospital, with very promising results. This consists of the intra- 

 venous injection of formalin in carefully-graduated strengths and 

 amounts. The effect, even in some very advanced cases, has been a rapid 



