THE TIME-FACTOR 3 1 



conditions. The effect induced by an external agent is, 

 moreover, modified by the duration of its influence. The 

 intensity of the reaction may thus increase at the first 

 stage, reach a climax and then undergo an actual decline. 

 No method had hitherto been available for immediate 

 detection and record of these changes, moment after 



Fig. 13. Record showing the effect of Carbonic Acid Gas on 



growth. 



Horizontal hne at the beginning indicates balanced growth. 

 Application of carbonic acid gas induces preliminary en- 

 hancement of growth, shown here by up-curve. The 

 growth-rate becomes normal for a while with subsequent 

 depression, shown by down curve. Successive dots at 

 intervals of 10 seconds. (Wheat.) 



moment, as they occur. The Method of Balance offers, in 

 this respect, unique advantages. 



The following are the characteristics of the curves 

 obtained by the balancing method. The initial horizontal 

 record indicates balance of the normal rate of growth ; 

 the delay in the responsive variation is the latent period ; 

 an up-curve represents enhancement of the rate of growth, 

 a down-curve indicating depression. If during the course 



