THE ELECTROCULTURE OF CROPS 619 



depends on the intensity of the agent and the length of time 

 during which it is applied ; further, that the effect of the 

 stimulus may first appear a considerable time after the appli- 

 cation. Molisch gives evidence that he possesses a good 

 knowledge of the living plant ; thus he realises that the same 

 agents react quite differently on a plant in its resting period, 

 in its period of germination, and during its active growth. 



Molisch, therefore, from his first empirical experiments which 

 showed that radium emanations would induce growth in a 

 resting organ (flower-buds) in winter time, does not conclude 

 that radium emanation will always have a beneficial influence 

 on plant life. He determines by a carefully planned series of 

 experiments that a definite quantity of radium emanation 

 applied for a definite period will induce the opening of flower- 

 buds ; but if the organ is not in its resting condition, application 

 of the emanation makes no difference in the rate of develop- 

 ment. Further series of experiments deal with the action of 

 various quantities of emanation applied over definite times, to 

 germinating seeds or growing seedlings. It was generally 

 found in these cases that a much smaller quantity of emanation 

 than that applied to resting organs has a distinctly harmful 

 effect and hinders development, but in the case of certain 

 species, with extremely small quantities of emanation a slightly 

 increased rate of growth was observed. 



It is not surprising that such a series of experiments should 

 have given rise all over the world to experiments on the value 

 of radio-active manure, but it is remarkable that some of the 

 investigators, in whose experiments an arbitrary and unknown 

 quantity of agent was used and which was allowed to act 

 throughout the whole season, should argue from the negative 

 results obtained by them that radium emanation is without 

 influence on plant life, and that Molisch 's experiments are 

 consequently disproved. 



There thus seems to be the possibility of the production of 

 a cycle of experiments, dealing with the use of radium emana- 

 tion, similar to that which already obtains in regard to electro- 

 culture, and this in spite of Molisch 's original well-planned 

 work. 



If we now take in review the electroculture experiments 

 and consider them in the light of the work on radium emanation 

 with which we have just dealt, we find that all investigators 

 41 



