213 



Physiological Investigations ivith Petiole- Pulvinus Preparations of 



Mimosa pudica. 



By Prof. J. C. Bose, M.A., D.Sc, C.S.I., C.I.E., assisted by Sueexdea 



Chaxdea Das, M.A. 



(Communicated by Prof. S. H. Vines, F.R.S. Received November 25, 1915.) 

 (From the Bio-physics Laboratory, Calcutta.) 



The essential similarity in the responsive reactions of plants and animals 

 which has been demonstrated in my previous works* leads us to expect that 

 the study of the simpler phenomena of irritability in the vegetal organism 

 may help in the elucidation of the more complex physiological reactions of 

 the animal. New methods of investigation found successful in the case of 

 plants may, moreover, prove to be equally applicable to the study of 

 reactions in animal tissues. This anticipation has been fully justified, since 

 it was my previous discovery of a method of inducing variation in the 

 conducting power of vegetable tissues that led me to the discovery of a 

 similar means of control of the excitatory impulse in the animal nerve.f 



My investigations on plant-irritability have hitherto been carried out with 

 entire plants. The most suitable plant for these researches is Mimosa pudica, 

 which can be obtained in all parts of the world. An impression unfortu- 

 nately prevails that the excitatory reaction of this plant can be obtained 

 only in summer and under very favourable circumstances, which has 

 militated against its extensive use in physiological experiments, but this 

 misgiving is without any foundation, for I found no difficulty in demon- 

 strating even the most delicate experiments on Mimosa before the Meeting 

 of the American Association for the Advancement of Science held last 

 Christinas at Philadelphia. The prevailing outside temperature at the 

 time was considerably below the freezing point. With foresight and care it 

 should not be at all difficult to maintain in a hot-house a large number of 

 these plants in a sensitive condition all the year round. 



* Bose, ' Plant Response,' 1906 (Longmans, Green, & Co.) ; ' Comparative Electro- 

 physiology,' 1907 (Longmans, Green, & Co.) ; 'Researches on Irritability of Plants,' 1913 

 (Longmans, Green, & Co.) ; "An Automatic Method for Investigation of Velocity of 

 Transmission of Excitation in Mimosa," ' Phil. Trans.,' B, vol. 204 (1913). 



t " The Influence of Homodromous and Heterodromous Electric Currents on Trans- 

 mission of Excitation in Plant and Animal," 'Roy. Soc. Proc.,' 1915. 



