( 293 ) 



On the Action of Chloroform on the Sensitive Plant {Mimosa 

 pudica). By Professor Marcet of Geneva.* 



When one or two drops of pure chloroform are placed on 

 the top of the common petiole of a leaf of the sensitive plant, 

 this petiole is seen almost immediately to droop, and an in- 

 stant after the folioles close successively pair by pair, begin- 

 ning w^ith those which are situated at the extremity of each 

 branch. t At the end of one or two minutes, sometimes more, 

 according as the plant is more or less sensitive, most of the 

 leaves next to the chloroformed leaf, and situated beneath it 

 on the same stalk, droop one after another, and their folioles 

 contract, although generally in a less complete manner than 

 those of the leaf placed in immediate contact with the chloro- 

 form. After a rather long time, varying according to the 

 vigour of the plant, the leaves open again by degrees ; but, 

 on trying to irritate them by the touch, it is seen that they 



publication of the important discoveries and observations of Professor James 

 Forbes. But the subject of the geological structure of these mountains is so 

 widely separated from that of glacial action, that I must crave a separate place 

 for the latter. When the occasion arrives, I shall endeavour to limit and cir- 

 cumscribe the extension of a certain hypothetical monster glacier of former 

 times, which, issuing from such narrow defiles as that of the Rhine, was sup- 

 posed to have spread out over the whole of the Canton de Vaud, and to have ad- 

 vanced to the Jura ; for although I believe that many of the Alpine glaciers 

 were formerly much more extensive than at the present day, their true ancient 

 boundaries can still be very well defined, I will farther try to prove that the 

 chief phenomena of erratic blocks around the Alps are the same as in the tracts 

 around Scandinavia and Lapland ; where, I hope, it has been clearly demon- 

 sti'ated that the blocks have been floated on ice-rafts ; and, lastly, it will be 

 proved, by recent facts, that, where large masses of gravel or drift slide over 

 the face of a rock, they produce exactly those striae, grooves, and polish, which 

 have been erroneously attributed to the action of glaciers only. 



London, 16 Belgrave Square, 

 Qth March 1849. 



* Read before the Soci6t6 de Physique et d'Histoire Naturelle, October 19, 

 1848, and communicated by Mr Marcet, junior. 



t I previously convinced myself by experiment, that a drop of water placed 

 delicately on a leaf of the sensitive plant, caused no movement. 

 VOL. XLVI. NO. XCII. — APRIL 1849. U 



