. IMPLICATIONS 141 



MODE OF ACTION OF SHORT RADIATIONS 



When the percentage of survivors is plotted against the total 

 energy used to kill yeast, typical S-shaped curves are secured from 

 the data of WyckofT and Luyet (1931) and Oster (1934). Several 

 different explanations of why curves of this type should be ob- 

 tained have been offered. Some workers regard them merely as 

 expressions of normal probability of survival of the individuals. 

 Others attribute the form of the curve to multiple quantum hits 

 on a sensitive region of the cell, presumably on the nucleus or cer- 

 tain of its constituent elements. A single hit is regarded as the 

 adsorption, by the sensitive region, of 1 quantum. The adherents 

 of the multiple-quantum theory, knowing the amount of energy 

 and the survival percentage, calculate the number of hits required 

 to kill. Needless to say there is little accord in observations on the 

 number of quanta required. The significance of this fact is not 

 clear, but the situation might be clarified if the influence of age, 

 nutrition, acidity, temperature, and such factors was taken into 

 consideration. In conclusion, it is apparent that many phenomena 

 attributed to the action of radiation are not caused by light alone 

 but are correlated in a causal relationship with other factors. 



IMPLICATIONS 



It appears that the present-day mycologist and physicist, each 

 in his own field, can do little more to extend knowledge of the ef- 

 fects of radiations on fungi. Conceivably they might achieve re- 

 sults were they to collaborate. In lieu of such collaboration, ad- 

 vances in knowledge will be conditional upon the presence of 

 workers who may properly be termed bio-physicists. This name 

 connotes possession of basic training in both biology and physics 

 and, what is more important, a consuming zeal to apply this 

 training to explorations leading to the furtherance and dissemina- 

 tion of knowledge in mycology. Such "myco-physicists" should 

 be able to correct or clarify many of the contradictory conclu- 

 sions and concepts now extant. 



