168 LIFE AND WORK OF SIR JAGADIS C. BOSE 



all forms of stimuli and the resulting response, which he 

 has demonstrated in the growth and life of ordinary plants. 

 Hence, too, the need of comparative study of all those 

 vegetable responses, not only in relation to each other, 

 but in comparison with the response of inorganic matter 

 on the one hand, and of animal muscle and nerve on the 

 other. But the study of such nervous phenomena, in 

 higher animals and in man, have long been under inquiry 

 by the psycho-physiologist or physiological psychologist ; 

 and if their organic substratum, their physiological pro- 

 cesses, be now demonstrated in the vegetable world, the 

 study of some of their elemental psychological bearings 

 can hardly but be of comparative and evolutionary 

 suggestiveness also. In this way Bose is widening out 

 our range of inquiry far beyond the initial outlooks of our 

 gardens ; or rather, let us say, those outlooks are deepening, 

 and beyond all previous anticipation. 



After this garden ramble, which might of course have 

 been extended to notice many other examples of plant - 

 movements, we start Bose (as it is happily easy to do, for 

 no man can be fuller of his subject, or more willing to 

 explain it) to give us a fresh outline of his discoveries and 

 their interpretations. He cannot begin better than with 

 his long-loved Mimosa ; and in this he first sets us clearly 

 to observe the form and movements. We note the long 

 leaf-stalk or petiole rising from the distinct and swollen 

 leaf -base or ' pulvinus/ which we soon find to be the 

 main sensitive organ, and especially its lower surface ; 

 we also see it to be the pivot from which the leaf falls. 

 Next, at the far end of the leaf-stalk, we note the four 

 secondary petioles, which answer to the two basal pairs 

 of pinnae in a compound Acacia leaf. As in this, they 

 bear on each side a row of small leaflets, the pinnules, of 

 which each has its base distinctly swollen, as a ' pulvinule.' 

 But the leaflets show up-movement, whether independently 

 excited, or when the main leaf falls. The main sensibility 



