134 LIFE AND WORK OF SIR JAGADIS C. BOSE 



movements, of which those of the Telegraph-plant 

 (Desmodium) are the extreme examples in the vegetable 

 world. Briefly stated, the automatism turns out to be but 

 apparent, in so far as these activities are proved to be 

 dependent on external stimulus previously absorbed. The 

 half-way house between this ' automatic ' activity and 

 the simple response of a Mimosa leaf was discovered in 

 Biophytum, a common weed of Bengal (akin to Oxalis) and 

 also in the somewhat allied Averrhoa Carambola, an acid 

 fruit-tree of Indian gardens. For while in these a single 

 moderate stimulus gives rise to a single response, as in 

 Mimosa, a strong stimulus produces a whole succession of 

 responses, recalling the automatism of Desmodium. This 

 observation suggested the idea that Desmodium might be 

 depressed in its automatism, and even reduced to the single 

 response of Mimosa ; and this condition was experimentally 

 realised : the leaflets ceased to pulsate accordingly, and 

 came to a standstill. Conversely, why should not Mimosa 

 have its simple response exalted towards a multiple 

 response, which is the transition stage on the way to autom- 

 atism ? This was not at first demonstrable mechanically, 

 but was proved by the electrical mode of response-record : 

 while now more lately, with the finer recorders since 

 invented, it has been successfully recorded in Mimosa. 

 That is, its natural single response is developed into a slow 

 rhythm of multiple response ; and this is practically 

 equivalent to the automatism induced in Biophytum. The 

 ascent of the whole series of sensitive plants from ordinary 

 (but as we now know, only apparently) insensitive ones, 

 first to simple response as in Mimosa, and thence through 

 transitional forms like Biophytum to the habitually auto- 

 matic Desmodium, has thus been made intelligible surely 

 no small gain to our conception of the evolutionary process. 



Another remarkable comparison is here also made 

 that between the automatic pulsation of the telegraph- 

 plant and that of animal heart-muscle. The comparison is 



