838 



SCIENCE 



[N. S. Vol. XXXIX. No. 1014 



will be explained by the deviation from Newton's 

 law already described. 



Behavior of Metals and Other Substances under 

 Stress Near the Rupture Point: A. A. Michel- 

 son. 

 On Highly Eadioactive Solutions: William Duane. 

 (Introduced by Professor Goodspeed.) 

 At the annual meeting last year the author 

 spoke on "Some Unsolved Problems in Eadioac- 

 tivity. ' ' At that time he stated that a number of 

 superficial cancers had been cured (some of them 

 only temporarily) by the proper application of a 

 sufficient quantity of radium, but that the prob- 

 lem of treating internal cancers had not been satis- 

 factorily solved. There appears, he said, to-day 

 to be no reason for changing that statement. 



Since that meeting the Cancer Commission of 

 Harvard University has purchased about 250 milli- 

 grams of radium element, and has been investi- 

 gating the effects due to the rays from radioactive 

 substances on tissues, using methods that the au- 

 thor has devised and that are somewhat different 

 from those employed before. He dwelt particu- 

 larly on one of these methods, namely, that in 

 which a concentrated radioactive solution is in- 

 jected into the tissues. 



Before describing the experiments he recalled 

 the following well-known facts. Firstly: radium 

 is continually transforming itself into a gas called 

 radium emanation, and this emanation is continu- 

 ally transforming itself in turn into a succession 

 of substances called radium A, B, C, etc., which 

 are grouped together under the general term ' ' de- 

 posited activity. ' ' These substances are radioac- 

 tive as well as the radium itself. Any sealed glass 

 tube containing radium contains these other radio- 

 active substances also. 



Secondly: these substances emit three types of 

 rays, the alpha, beta and gamma rays. The alpha 

 rays carry with them about 90 per cent, of the 

 energy of the radiation, and the other 10 per cent. 

 is divided between the beta and gamma rays. The 

 alpha rays, however, are the least penetrating of 

 the three types ; they are stopped by about 1/25 of 

 an inch of ordinary flesh. 



Thirdly: radium, the emanation and radium A 

 practically emit alpha rays only. Eadium B emits 

 weak beta and gamma rays and no alpha rays ; but 

 radium C emits all three kinds and is by far the 

 most powerful radiator of the whole group. In 

 the ordinary application of radium to tumors the 

 methods are of such a nature that the alpha rays 

 are absorbed before they reach the tissues, and 

 the beta and gamma rays, therefore, are the only 



ones used. Hence over 90 per cent, of the energy 

 is wasted; and further the rays that are used 

 come exclusively from radium B and C, and not 

 from the radium itself or from the emanation. 



The emanation and deposited activity can be 

 separated from the radium and used alone. The 

 method the author has perfected for doing this is 

 as follows : The radium salt itself is in solution in 

 a small glass tube, from which the air has been 

 completely exhausted. Under these circumstances 

 the emanation escapes from the solution. A 

 simple mercury pump pumps the emanation into 

 a second tube containing phosphor pentoxyd and a 

 copper wire heated red hot by an electric current. 

 The hot wire absorbs the hydrogen and oxygen 

 that have been produced by the decomposition of 

 the water, and the pentoxyd absorbs the water 

 vapor. After purification a second pump pumps 

 the emanation into a small glass bulb containing 

 a few grains of common salt. The emanation re- 

 mains in contact with the salt for several hours, 

 depositing radium A B C on it. The salt thus be- 

 comes very radioactive, and on being removed 

 from the bulb and dissolved in a small amount of 

 water carries with it the activity, thus making the 

 solution itself radioactive. 



He has used several other methods of making 

 these radioactive solutions. The deposited activity 

 may be deposited on sodium hydroxide, and this 

 may be dissolved in a few drops of water contain- 

 ing just enough hydrochloric acid to neutralize the 

 hydroxide; or the emanation may be sealed into a 

 small glass bulb with a capillary glass tube at- 

 tached. If this is placed under water or a saline 

 solution and the capillary tube broken, the liquid 

 runs up into the bulb and dissolves the emanation, 

 forming a radioactive solution. Solutions made 

 by these methods may be millions of times more 

 active than those hitherto used. In fact, they may 

 be made weight for weight far more active than 

 any solution containing radium itself could be. 



The advantage in using these solutions in study- 

 ing the effects produced on tissues is that after 

 injection the radioactive substances come into inti- 

 mate contact with the tissues, and thus the full 

 power of the alpha rays is utilized. 



If a solution of radium itself is injected, the 

 process is not only costly, but very dangerous on 

 account of the long life of the radium. The de- 

 posited activity solutions do not have these ob- 

 jections, for the radium is not wasted in produc- 

 ing the solutions and the activity lasts for only 

 a short time. 



He made a number of experiments to find out 



