DETECTION OF LATENT STIMULUS 



463 



acceleration that precedes it. Incidentally, we see here the 

 difference between the temperature-effect per se, and the 

 stimulating effect of sudden variations of temperature, con- 

 stituting thermal shocks. 



In the simple case we have just studied, where the whole 

 amount of incident stimulus was expressed in work external 

 and internal, without any loss from molecular friction, the 

 sum total of the two forms of response was found approxi- 

 mately the same under a constant stimulus ; but in other 

 cases, where a certain amount of energy is wasted in over- 

 coming molecular sluggishness, the results will be slightly 

 different, for at a temperature below the optimum a por- 

 tion of the stimulus will be wasted in overcoming such 

 sluggishness, whereas near the optimum temperature the 

 loss entailed on this account will be very slight. Hence, the 

 sum of direct and indirect responses, near the optimum, will 

 in such cases be somewhat greater than at a temperature 

 several degrees lower. I give below a table which shows at 

 a glance the direct effect and the indirect after-effect, 

 obtained at the three temperatures of 30 C, 35 C, and 

 37 C. respectively, with three different specimens, one of 

 which was a rice-seedling {Oryza sativa), and the two others 

 flower-buds of Crinum Lily. Each response given is the 

 mean of three. 



Table showing Direct and Indirect Effects at Three Different 

 Temperatures 



Specimen 



i. Seedling of 

 Oryza sativa 



Tempera- 

 ture 



2. Crinum Lily 



f 30° c. 



3. Crinum Lily -j 35 C. 

 I 37° C. 



Direct effect 



(retardation of 



growth) 



18 divisions 



28 



12 



Indirect effect 



(acceleration of 



growth) 



10 divisions 

 6-5 „ 



13-5 divisions 



8-5 

 o 



Total effect 



17 divisions 



13 



o 



