THE DEDICATION 237 



electric receiver made of galena was the forerunner of 

 ,the application of crystal detectors for extending the range 

 of wireless signals. In physical chemistry the detection of 

 molecular change in matter under electric stimulation 

 led to a new theory of photographic action. The fruitful 

 theory of stereo-chemistry was strengthened by the pro- 

 duction of two kinds of artificial molecules, which like the 

 two kinds of sugar, rotated the polarised electric wave 

 either to the right or to the left. Again the ' fatigue ' of 

 my receivers led to the discovery of universal sensitiveness 

 inherent in matter as shown by its electric response. It 

 was next possible to study this response in its modification 

 under changing environment, of which its exaltation under 

 stimulants and its abolition under poisons are among the 

 most astonishing outward manifestations. And as a single 

 example of the many applications of this fruitful discovery, 

 the characteristics of an artificial retina gave a clue to the 

 unexpected discovery of ' binocular alternation of vision ' 

 in man ; each eye thus supplements its fellow by turns, 

 instead of acting as a continuously yoked pair, as hitherto 

 believed. 



PLANT LIFE AND ANIMAL LIFE 



In natural sequence to the investigation of the response 

 in ' inorganic ' matter, has followed a prolonged study of 

 the activities of plant-life as compared with the corre- 

 sponding functioning of animal life. But since plants for 

 the most part seem motionless and passive, and are indeed 

 limited in their range of movement, special apparatus of 

 extreme delicacy had to be invented, which should magnify 

 the tremor of excitation and also measure the perception 

 period of a plant to a thousandth part of a second. Ultra- 

 microscopic movements were measured and recorded ; 

 the length measured being often smaller than a fraction 

 of a single wave-length of light. The secret of plant-life 

 was thus for the first time revealed by the autographs of 



