RADIANT ENERGY 415 



it is superficial in origin. Also, a cell may not in itself be capable 

 of radiation but may be aroused to emanation activity by a 

 neighboring radioactive cell. The secondary radiation may be 

 greater than the primary. 



The number of known kinds of receptors has not, strange to 

 say, increased with that of the senders. Yeast is the most 

 satisfactory receptor. Bacteria also respond well. 



The work of Gurwitsch has been so severely criticized that it 

 will be well to let the matter rest until future research establishes 

 its truth or falsity. Numerous investigators in Russia, Germany, 

 Holland, and elsewhere support the work with experiments of 

 their own, but others are unable to prove the results. 



In judging the value of criticism, we must distinguish between 

 a purely emotional reaction without experimental work to sup- 

 port it and carefully carried out research. Most of the opposi- 

 tion to Gurwitsch is of the former sort, though some is of the 

 latter kind. The problem is too interesting a one to let it go 

 without some, if need be purely theoretical, consideration. 



The hypothesis that living matter gives off radiant energy 

 may be approached deductively. The chemical constituents of 

 protoplasm include potassium and rubidium, both slightly 

 radioactive. Knowledge of the presence of these elements in 

 living matter is of long standing. Traces of radium have recently 

 been found in living plants and animals. McCoUum showed 

 that potassium is mobilized where mitosis is at a maximum 

 (this was before it was known that potassium is radioactive), and 

 Kroetz showed experimentally that X rays and ultraviolet are 

 effective in mobilizing potassium at the expense of calcium. If 

 we assume the potassium content of muscle tissue to be 0.3 per 

 cent, we can account for beta radiation alone equivalent to a 

 possible maximum of 36,000 light quanta per square centimeter 

 per second. Most of this radiation probably appears as second- 

 ary energy of a different wave length. 



Every chemical reaction involves a transfer of energy which 

 may manifest itself in the form of heat, light, or an electrical 

 potential. The chemist is quite familiar with radiations that 

 produce fluorescence, e.g., sodium chloride crystals when exposed 

 to roentgen rays. Fluorescence also occurs when sodium is 

 burned in the presence of chlorine. Chemoluminescence is an 

 ever growing chapter in present-day chemistry. W. C. Lewis 



