LEGUMINOS^E. CCXXIII. MIMOSA. 



383 



form the whole mass of vegetable tissue, and that the same acid 

 produced other effects equally advantageous for the examination 

 of the most obscure parts of vegetable structure, he was induced 

 to give his attention to that of Mimosa pudica, in the hope of 

 gaining some evidence respecting the cause to which its sensi- 

 bility is to be ascribed. Beginning with the pith he observed a 

 considerable number of minute globules, of a greenish colour, 

 intermingled among the cells, and adhering to them in an irre- 

 gular manner. After attempting to show the probability of 

 these globules having deceived Mirble in various points of his 

 analysis of vegetation, and especially in regard to the pores, 

 which that botanist supposes to exist in the cellular tissue of 

 plants, Dr. Dutrochet proceeds to remark, that the application of 

 hot nitric acid to these globules renders them perfectly opaque, 

 whence he concludes that they are in fact minute cells, filled 

 with a particular fluid which is subject to become concrete by 

 the application of acids. Now it is known that such fluids as 

 are thus altered by acids are usually dissolved and liquefied 

 again by the application of alkalies. A few drops, therefore, of 

 a solution of hydrate of potass were suffered to fall upon a 

 portion of the pith on which nitric acid had been acting, and the 

 mixture was exposed to the heat of a lamp. Being examined 

 after a few minutes, the globules were found to have resumed 

 their natural appearance. This curious fact indicated, in the 

 opinion of Dutrochet, a strong and unexpected point of analogy 

 between plants and animals. According to the microscopical 

 researches of some modern observers, it has been ascertained 

 that all the organs of animals are composed of a conglomeration 

 of minute corpuscles, similar to those just described ; the cor- 

 puscles which constitute the muscles are soluble in acids, but 

 those which compose the nervous system are insoluble in the 

 same acids, and only soluble in alkalies. Now, as the chemical 

 properties and external appearance of the particles scattered 

 among the cellular tissue of plants, and constituting the nervous 

 system of animals, are the same, the author is induced to infer, 

 that the spherical particles of plants are in fact the scattered 

 elements of their nervous system. This hypothesis receives 

 additional strength from the great similarity which exists between 

 the medullary substance of the brain of Molusca gasteropoda 

 and the cellular medullary tissue of plants. In pursuit of 

 this idea, Dr. Dutrochet made a variety of experiments upon 

 the sensitive plant, the results of which seem to be these: 

 The principal point of locomotion or of mobility exists in the 

 little swelling which is situated at the base of the common and 

 partial petioles of the leaves ; this swelling is composed of a 

 very delicate cellular tissue, in which is found an immense num- 

 ber of nervous corpuscles ; the axis of the swelling is formed 

 of a little fascicle of tubular vessels. It was ascertained by 

 some delicate experiments, that the power of movement, or of 

 contraction and expansion, exists in the parenchyma and cellular 

 tissue of the swelling, and that the central fibres have no spe- 

 cific action connected with the motion. It also appeared that 

 the energy of the nervous powers of the leaf depended wholly 

 upon an abundance of sap, and that a diminution of that fluid 

 occasioned an extreme diminution of the sensibility of the leaves. 

 Prosecuting his remarks still further, the author ascertained that 

 in the motion of the sensitive plant two distinct motions take 

 place, the one of locomotion, which is the consequence of direct 

 violence offered to the leaves, and which occurs in the swellings 

 already spoken of; the other is nervimotion, which depends 

 upon some stimulus applied to the surface of the leaflets, unac- 

 companied by actual violence, such as the solar rays concentrated 

 in the focus of a lens. As in all cases the bending or folding 

 of the leaves evidently takes place from one leaf to another 

 with perfect continuity, it may safely be inferred, that the in- 

 visible nervous action takes place in a direct line from the point 



of original irritation, and that the cause by which this action of 

 nervimotion is produced must be some internal uninterrupted 

 agency. This was, after much curious investigation, determined 

 by the author to exist neither in the pith nor in the bark, nor 

 even in the cellular tissue filled with nervous corpuscles, and on 

 which he supposes the locomotion of the swelling at the base 

 of the petioles to depend. It is in the ligneous part of the cen- 

 tral system in certain tubes supplied with nervous corpuscles, 

 and serving for the transmission of sap, that Dr. Dutrochet be- 

 lieves he has found the true seat of nervimotion, which he attri- 

 butes to the agency of the sap alone, while he considers the 

 power of locomotion to depend upon the nervous corpuscles 

 alone. 



Far. ft, glabrata (D. C. prod. 2. p. 426.) stem glabrous. Na- 

 tive of St. Domingo and St. Thomas. Plum. ed. Burm. t. 202. 



I'ar. y, tetrandra (Willd. spec. 1. p. 1032.) leaflets clothed 

 with adpressed pili beneath. M. pudica, H. B. et Kunth, nov. 

 gen. amer. 6. p. 252. 



Chaste or Common Humble-plant. Fl. April, Sept. Clt. 

 1638. PI. 1 foot. 



13 M. HISFIDULA (H. B. et Kunth, nov. gen. amer. 6. p. 252.) 

 stems prickly, and densely beset with stiff hairs ; leaves some- 

 what digitately pinnate, with 4 pinnae ; leaflets linear, acute, 

 ciliated, glabrous ; heads of flowers usually twin ; legumes very 

 hispid. Tj . S. Native of South America, near Santa Barbara. 

 Very nearly allied to M. pudica. Flowers red. 



Hispid Humble-plant. Fl.May, Sept. Clt. 1820. Sh. 1 to 2 ft. 



14 M. PUDIBU'NDA (Willd. spec. 4. p. 1032.) stem shrubby, 

 prickly, glabrous ; leaves somewhat digitately pinnate, with 4 

 pinnre, each pinna bearing many pairs of linear leaflets ; heads 

 of flowers elliptic. Tj . S. Native of Brazil, about Bahia. 

 Flowers red. 



Blushing Humble-plant. Fl. Ju. Aug. Clt. 1818. Sh. 1 to 2 ft. 



15 M. TOMENTOSA (Humb. et Bonpl. in Willd. spec. 4. p. 

 1033.) branches unarmed, clothed with silky hairs ; leaves some- 

 what digitately pinnate, with 4 pinnae, each pinna bearing many 

 pairs of oblong-linear leaflets, which are clothed with hoary silky 

 villi beneath, fj . S. Native of South America, on the banks of 

 the river Orinoco. Kunth, mini. p. 11. t. 4. H. B. et Kunth, 

 nov. gen. amer. 6. p. 253. Flowers red. Legumes unknown. 

 The specific name is fallacious. 



Tomentose Humble-plant. Shrub. 



16 M. HIRSU'TA (Moc. etSesse, in herb. Lamb.) prickles sti- 

 pular, recurved ; leaves with only 1 pair of pinna;, each pinna 

 bearing numerous linear, mucronate leaflets ; stem hispid as well 

 as the pedicels, petioles, and rachis of leaves ; peduncles solitary 

 or twin, axillary, about the length of the petioles ; calyx hispid ; 

 legumes prickly on the margins, 3-4-jointed. Q. S. Native 

 of Mexico. Heads of flowers nearly globular, red. 



Hairy Sensitive-plant. PI. 1 to 2 feet. 



17 M. TRICE'PHALA (Schlecht. et Cham, in Linnaea. 5. p. 591.) 

 leaves with 1 pair of pinna;, each pinna bearing 12 pairs of oblique, 

 ovate-elliptic, mucronate leaflets, which are adpressedly ciliated 

 on the margins, shining and glabrous above, but strigose beneath ; 

 petiole short ; stipulas small, filiform ; branches, rachis of leaves, 

 and peduncles scabrous from stiff hairs ; heads tern, on long 

 peduncles, axillary, and forming a loose terminal raceme, which 

 is leafy at the base. Jj . S. Native of Mexico, between Laguna, 

 Verde, and Actopan. Flowers pale red. Legumes unknown. 



Three-headed Mimosa. Shrub. 



18 M. POLYDA'CTYLA (Humb. et Bonpl. in Willd. spec. 4. 

 p. 1033.) stems prickly, glabrous, pilose above ; leaves some- 

 what digitately pinnate, with 8 pinna;, each pinna bearing many 

 pairs of linear leaflets. ^ . S. Native of Guiana, and about 

 Demerara, as well as in Maranham. Flowers purple. Heads 

 of flowers twin, ovate, pedunculate. 





