279 



This distribution of the radioactivity in the plant body is con- 

 stant, and the authors consider that there is in the plant a special 

 substance, sensible to the emanation, and capable of becoming 

 radioactive under its influence. This substance occurs in the 

 roots, but gradually diminishes up the stem. It is found also in 

 seeds. According to this same paper plants possess a natural 

 radioactivity, which is distributed throughout the plant similarly 

 to the induced radioactivity. This natural radioactivity is strong 

 enough to affect a photographic plate, and plays an important 

 role in the development of the plant. 



In a second paper Russel*' gives a list of 33 native and 22 

 foreign woods that are active, and says that the activity of resins 

 and gums is increased by exposui'e, not only to sunlight, but to the 

 arc-light as well. Photographic plates often contain a negative of 

 the plate-holder. That this is not a case of radioactivity appears to 

 be proved, says the author, for a glass or a mica screen of one 

 thousandth of an inch in thickness entirely protects the plate from 

 being acted on. 



Finally Paul BecquereP undertook a careful study of "plant 

 radioactivity." He tested pea seeds, moss {Hypnuvi), and 

 branches of boxwood for radioactivity, but found not a trace of 

 it manifest when the electroscope was carefully guarded from 

 water-vapor. This explains the condition found necessary by 

 Tommasina, that the parts of plants must be freshly picked in 

 order to manifest bio-radioactivity. According to Becquerel, the 

 discharge of the electroscope in Tommasina's experiments was 

 due to the water in the plants. 



From all the investigations noted above, the general conclusion 

 seems to be warranted that radioactivity is not a property of proto- 

 plasm nor of living tissues. A clear understanding of the nature 

 of radioactivity would lead, a priori, to the same inference. 



2. The Professed Artificial Creation of Life 



Radioactivity and vital activity are in two respects very 

 roughly, but only very superficially analogous. Both radio- 

 active bodies and living organisms are undergoing a destructive 

 process ; atomic disintegration in the one, molecular transforma- 



