V- ( 380 ) 



On the Irritability of the Sensitive Plant. By M. Dutbochet. 



i-VA- DuTRocHET has collected, into a single volume, the long 

 and important researches which he has made upon the moving 

 powers which act in organised bodies. His experiments on the 

 sensitive plant occupy an essential part of this work. A new 

 procedure, which he has employed in vegetable anatomy, has led 

 him to results which would tend to invalidate a celebrated the- 

 ory. He asserts, that all the elementary organs of plants, that 

 is to say, the cellules and tubes, of which their body is composed, 

 have an independent existence, and form circumscribed organs ; 

 so that these organs would only have, to each other, relations of 

 vicinage, and would not form, by their assemblage, a really con- 

 tinuous tissue. He affirms that there are neither pores nor fis- 

 sures visible to the microscope in the cellular tissue, any more 

 than in the fibres of vegetables. There are only seen on the 

 walls of these organs, small semitransparent globular bodies, and 

 linear bodies, which become opaque from the action of acids, and 

 are rendered transparent by that of alkalies. M. Dutrochet con- 

 siders these small bodies as the elements of a diffused nervous 

 system. To the analogies of intimate structure and chemical 

 nature, which he brings forward to support this opinion, the au- 

 thor adds physiological considerations, taken from experiments, 

 which are peculiar to himself, and which, in his opinion, prove 

 that the motions of vegetables are spontaneous ; in other words, 

 that they depend upon an internal principle, which immediately 

 receives the influence of external agents. Refusing to admit 

 sensibility in vegetables, M. Dutrochet substitutes for this term 

 that of nervimotility. 



With regard to the organ of motion in the leaves of the sen- 

 sitive plant, M. Dutrochet has proved, by decisive experiments, 

 that it consists in a bulging of the parenchyma, or of the cortical 

 medulla, which is situated at the base of the petiole, and at the 

 base of each of the leaflets of 'which the leaf is composed. He 

 has discovered, that this organ, to which he has given the name 

 of bourrelet, is composed of globular cellules, disposed in longitu- 

 dinal series, and filled with a coagulable fluid. It is not by 

 means of joints that the sensitive plant, any more than the other 

 irritable vegetables, moves its mobile parts ; but by means of a 



