UNSUSPECTED KADIATIOTSTS. 379 



a good radiograiu, and the morbid ettec-t« have been traced by Russian 

 explorers (Danilev.skv. Tarkhanoff) to electric radiations aitog-ether, 

 rather than to the X-rays themselves. Formerly it required eighteen 

 minutes to obtain a radiogram of the hand. Now we are told that Dr. 

 Donath oljtains in two seconds a distinct radiogram of so difficult a 

 subject as the shoulder and the chest; while Tesla, with his powerful 

 alternate currents, could show distinct shadows at a distance of 1(>.5 feet 

 from the vacuum tube. In the hands of an a])le surgeon — as Prof. 

 E. Bergmann illustrated before the Association of German Naturalists 

 and Physicians in 1899 — the X-rays become a most precious means of 

 exploration. The growth of the bones, from l>irth till matured age, 

 could be studied with their aid, and the various causes which retard 

 groAvth (rachitism, tuberculosis) or produce midgets could 1)0 ascer- 

 tained. The fearful splintering of the bones by the modern l)ullets, 

 and especially by the English dumdum bullet, became known, and the 

 radiograms of Bruns showing the effects of the dumdum provoked 

 on the Continent a unanimous indignation against this Imllet. Man}^ 

 limbs were saved during the last Greek-Turkish war by Nasse and 

 Kiittnci- contiiuially resorting to radiograph3\ So also in the Soudan 

 war. In fractures of the kneecap the Rontgen ra\'s have proved sim- 

 ])\y invaluable, but perhaps the best service the}^ rendered was to 

 demonstrate that in many cases it was far preferable to leave pellets 

 of lead, small revolver bullets, and even Peabody-Martini ))ullets 

 where they were lodged in the tissues instead of trying to get them 

 out. In fact. Dr. Bergmann's radiograms prove that a bullet may 

 sometimes remain in the lungs without occasioning any trouble. Such 

 was the case of a German soldier who had carried a bullet in his lungs 

 for twenty-nine years, since 1871, without knowing it. The German 

 professor goes even so far as to maintain that there are cases when a 

 small bullet lodged in the white mass of the brain will remain there 

 firmly imbedded, without producing any noticeable trouble, and that 

 there is less danger in leaxing it there than in extracting it. 



If Rontgen's discovery had only the effect of alleviating so many 

 human miseries, it would already rank among the great achievements 

 of th(^ century, but its profound effects upon natural philosophy are 

 far from being yet exhausted. 



Every one knows the phosphorescent match boxes provided with a 

 white surface, which is. usually protected from moistuie by a glass, 

 and glows in the darkness, making the box visible at night. Suli)liide 

 of lime is generally used for making such glowing surfaces, but vari- 

 ous compounds of barium, calcium, strontium, uranium, and so on 

 possess the same property of glowing in the dark after they have been 

 exposed for some time to light. They are said in this case to '^ store 

 up" light energy, which the}' give awa}' afterwards; this was, at least, 



