CURRENT LITERATURE 
BOOK REVIEWS 
Irritability of plants 
The experimentation described in BosE’s new volume’ is marked by excel- 
lence of methods and execution. The presentation is in direct, clear, and in 
any places elegant English. The findings are rendered quickly available by 
comprehensive but concise summaries at the end of each chapter and at the 
end of the volume. One regrets that this excellent work is marred here and 
there by oldness of viewpoint and lack of knowledge of physiological literature. 
In his older researches Bose used the optical lever with the photographic 
method of recording. This made the taking of automatic records tedious, 
with the possibility of relatively few records during the active season of the 
plant. It also forced experimentation in an abnormal condition for the plant, 
namely, continual darkness. The resistance offered by the recording appara- 
tus, both because of weight of the arm and because of the friction of the writing 
point on the black surface, was another difficulty in the taking of automatic 
records. The author has overcome all of these difficulties by his new and 
ingenious resonant and oscillating recorders. He has designed arms that are 
about 0.01 as heavy as those used with the muscle nerve, and the oscillating 
or resonant recorder gives a series of dots on the black surface rather than a 
continuous line. This reduces the friction to a very small fraction of that of 
the continuous record. In the Desmodium leaflet the author has shown that 
a continuous line gives a great reduction in the magnitude of the movement, 
while none occurs with the new recorder. His new apparatus also makes 
possible the recording of periods as short as 0.001 of a second. One is con- 
vinced that Bose is reaching the optimum of accuracy and delicacy in the 
matter of automatic records of plant response, and this is much needed, for 
many fewer such records exist for plants than for animals. 
This excellent experimentation results in a number of things of interest to 
plant physiologists; in some cases confirming views already held; in others 
showing prevailing views at error; and in still others giving exact determina- 
tions of physiological critical time periods. Bose shows that the sum of 
stimulus law holds for a number of stimuli, as has been shown to be the case 
for geotropism, heliotropism, etc. In subtonic condition of an organ the 
stimulus itself renders the organ more excitable to the same stimulus. He h 
apparently established beyond doubt that conduction of a stimulus in the 
Bose, J. C., Researches on irritability of plants. xxxiv-+376. figs. 190. Lon- 
don: Longmans, Green & Co. 1913. 
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