PREFACE
A COLLECTION of papers mainly physical, dating from the year 1895, is published in the present volume. The first object of my inquiry was the optical properties of Electric Waves, brought down to within a few octaves of visible light. In the course of my investigations I was led to the discovery of electric response of non-living matter, such as metals, an account of which was published in 1900 by the International Congress of Science, Paris. The response, like that of living matter, was shown to exhibit fatigue under continuous stimulation, enhancement under chemical stimulants, and permanent abolition under poisons. These results indicated that the response of the more complex and unstable living matter is ultimately the expression of physico-chemical reactions.
My subsequent investigations were directed towards the establishment of the generalisation of the essential unity of physiological mechanism in plant and animal life. The reaction of living tissues, is greatly complicated by the combined effects induced by the fluctuating changes of the environment. This accounts for the complexity of life-movements, which are by no means capricious but are capable of rational explanation by the discovery of the combined action of different factors, the individual reactions to which are unknown to us. The external conditions can be maintained constant for only a short time during which the effect of variation of an individual factor has to be determined. This necessitates special devices for exceptionally high
