

Chemistry and Physics. 115 



and at Seamick in Moldavia, in layers of bituminous schists, and is de- 

 scribed with the same properties by Oken under the name of ozocerite 

 (Hatchetine.) The authors however are of opinion that the muriatic 

 acid used for these experiments has no influence on the production of 

 this wax-like substance, which the authors have provisionally called 

 artificial ozocerite. 



17. On the Action of Chloroform on the Sensitive Plant {Mimosa 

 pudica) ; by Professor Marcet of Geneva, (read before the Societe de 

 Physique et d'Histoire Naturelle, Oct. 19, 1848, and communicated by 

 the author to Phil, Mag., xxxiv, 130, Feb., 1849.)— When one or two 

 drops of pure chloroform are placed on the lop of the common petiole 



of a leaf of the sensitive plant, this petiole is seen almost immediately 

 to droop, and an instant after the folioles close successively pair by 

 pair, beginning with those which are situated at the extremity of each 

 branch.* At the end of one or two minutes, sometimes more, accord- 

 ing 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 chloroform. After a rather long time, varying according to 

 the vigor of the plant, the leaves open again by degrees ; but on trying 

 to irritate them by the touch, it is seen that they have become nearly 

 insensible to this kind of excitement, and no longer close as before. 

 a hey thus remain as torpid for some time, and generally do not recover 

 their primitive sensitiveness till after some hours. If, however, when 

 they are in this state of apparent torpidity, they are subjected again to 

 the action of the chloroform, they close as they did the first time. It 

 l s not till after they have been chloroformed several times, that they 

 lose all kind of sensitiveness, at least until the next day ; sometimes 

 they even fade completely at the end of too frequent repetitions of the 

 experiment. In all cases the effects observed are the more marked in 

 proportion to the purity of the chloroform employed and the degree of 

 sensitiveness in the plant. 



An analogous phenomenon is produced if, instead of placing the drop 

 °f chloroform on the base of the petiole, it is laid on the folioles situa- 

 ted at the extremity of a branch. The folioles of this branch immedi- 

 ately begin to close pair by pair, the common petiole droops, lastly the 

 folioles of the other branches close in turn. At the end of two or 

 three minutes, the nearest opposite leaf, and if the plant is vigorous, 

 most of the other leaves situated below on the same stalk follow their 

 example. When, after some time, the leaves open again, the same 

 w *nt of sensitiveness is manifested as in the preceding case. 



A singular feature in this phenomenon is the manner in which the 

 ac tion of the chloroform is propagated from one branch to another, 

 th en from one leaf to another, even when the liquid disappears by 

 evaporation almost as soon as it is deposited. This action, as we have 

 f* seen, appears to be communicated from the leaf to the stalk, fol- 

 ding in the latter a descending direction ; generally the leaves situa- 



* I previously convinced myself bv experiment that a drop of water, placed deli 

 le[ y on a leaf of the sensitive plant, caused no movement. 



