156 LIFE AND WORK OF SIR JAGADIS C. BOSE 



Peculiarly obvious is the result of any temperature 

 change upon the rate of growth. The application of cooled 

 water of course depresses, until at the critical minimum 

 all growth is arrested. Conversely, warmed water may 

 effect an astonishingly rapid increase of growth, even by 

 many times, up to the optimum ; beyond which growth 

 is increasingly retarded, until at about 60 C. the death- 

 spasm appears. 



By a further refinement of experimentation, an auto- 

 matic method provides records of a plant's growth during 

 gradual increase of temperature from minimum to maxi- 

 mum ; and the inspection of this ' Thermo-crescent Curve ' 

 informs the observer of the rate of growth at each and 

 every temperature. The method hitherto employed was 

 to place batches of plants to grow for a day in different 

 temperatures, and to average the results of each batch ; 

 but the new method is at once far simpler, speedier and 

 far more accurate. 



Similarly the effect of manures and chemicals, drugs 

 and poisons, may now each be determined in the course of 

 a few minutes, and with unprecedented accuracy. Here 

 too, as in the preceding cases, we realise the value of this 

 high magnification apparatus : not merely because all 

 the phenomena are rendered far clearer and more con- 

 spicuous, but also because the result of any particular 

 change of conditions can be detected in the course of a few 

 minutes, during which the other conditions may remain 

 constant, or be artificially kept so. 



It will be understood that it is only by the discovery of 

 laws of growth that any marked advance in scientific 

 agriculture is possible. We have been using only a few 

 stimulating agents, whereas there are thousands of whose 

 actions we have no conception. The rule of thumb method 

 hitherto employed in the application of a few chemical 

 stimulants and of electricity has, moreover, not been 

 uniformly successful. The cause of the anomaly is found 

 from the discovery of an important factor namely, the 



