of recording time-intervals as short as a thousandth part of a second. A brief account of this is given in my paper "On an Automatic Method for the Investigation of the Velocity of Transmission of Excitation in Mimosa," read before the Royal Society. It will be recognised immediately in how many directions our power of inquiry has become extended by the elaboration of these new methods and the invention of several types of instrumental appliances described in this work.
In presenting the results of these investigations, it will be noted that the plant has been made to tell its own story, by means of its self-made records. Each experiment has been repeated at least a dozen times, in many cases as often as a hundred times. The results may therefore be accepted as fully attested. The establishment of the unity of responsive reactions in the plant and animal, which is the subject of this work, will be found highly significant, since it is only by the study of the simpler phenomena of irritability in the vegetal organisms that we can ever expect to elucidate the more complex physiological reactions in the animal tissues.
I take this opportunity to thank my research assistants, Messrs. Guruprasanna Das, L.M.S., and Surendra Chandra Das, M.A., for the very efficient help rendered by them in these researches.
Presidency College, Calcutta,
October 1912.
