SEN 



(hut up its leaves a little, but never in any very great decree. 

 The plant, however, is kail of all afFefted about nine o'clock; 

 in the morning, and that is confequently the propereft time 

 to make experiments on it. A branch of the fenfmve piant 

 cut off, and laid by, retains yet its property of fhuttmg up 

 and opening in the morning for fome days ; and it holds it 

 longer if kept with one end in water than if left to dry more 



fuddenly. • . • u 



The leaves only of the fenfitive plant Ihut up in the night, 

 not the branches ; and if it be touched at this time, the 

 branches are affefted in the fame manner as in the day, Ihut- 

 tiag up, or approaching to the ftalk or trunk, in the fame 

 manner, and often with more force. It is of no confe- 

 quence what the fubltance is vfith which the plant is touched, 

 it anfwers alike to all ; but there may be obferved a little 

 fpot, ditlinguifhable by its paler colour in the articulations of 

 its leaves, where the greateft and niceft fenfibility is evidently 

 placed. 



The fenfitive plant plunged into water immediately clofes 

 its leaves, which is partly owing to the touch, partly to the 

 coldnefs of the water ; afterwards the leaves expand again, 

 and if they are then touched, clofe again as before, as if in the 

 open air, only that they do it with lefs force. 



If the end of one of the leaves be burning with the flame 

 of a candle, or by a burning glafs, or touching it with hot 

 iron, it clofes up in a moment, and the oppofite leaf does the 

 fame, and after that the whole feries of leaves on each of the 

 rib, then the rib itfelf, then the branch, all do the fame, if 

 the burning has been in a fufficient degree. This proves 

 that there is a very nice communication between all the parts 

 of the plant, by means of which the burning, which only is 

 applied to the extremity of one leaf, diffufes its influence 

 through every part of the (hrub. 



If a drop of aqua fortis be carefully laid upon a leaf of the 

 fenfitive plant, fo as not to (hake it in the leaft, the leaf does 

 not begin to move till the acid liquor corrodes the fubftance 

 of i\ ; but at that time, not only that particular leaf, but all 

 the leaves placed on the fame rib, clofe themfelves up. The 

 vapour of burning fulphur has alfo this efFeft on many leaves 

 at once, according as they are more or lefs expofed to it ; 

 but a bottle of very acrid and fulphureous fpirit of vitriol, 

 placed under the branches unftopped, produces no fuch 

 effcd. 



The wetting of the leaves with fpirit of wine has been ob- 

 ferved alfo to have no effeft, nor the rubbing oil of almonds 

 over them ; though this laft application deftroys many 

 plants. 



A branch of the plant was cut away longitudinally, till 

 only a third part of the fubllance remained, yet it commu- 

 nicated the effeAs of the touch, in the fame manner as be- 

 fore, to thofe branches which arofe lower on the (hrub. 

 The tranfjjiration of the plant being retarded, is of no effeft 

 as to its periodical opening and clofing ; for one kept under 

 a clofe glafs bell (huts and opens as regularly night and 

 morning, as wlien it (lands in an open green-houfe. A 

 brancli of it put into the exhaulled receiver of an air-pump, 

 is found lo have its force of opening and clofing up much 

 impaired, but not wholly taken off. Mem. de I'Acad. des 

 Scienc. Par. 1736. 



Dr. Hill, notwithllanding the experiments and obferva- 

 dons above recited, confiders the phenomenon of the fen- 

 fitive plant as the effeft of hght, and in an exprefs difl'ertation 

 on this fubjeft, endeavours to a<:count for it from this prin- 

 ciple ; afcribing that other phenomenon, which is called the 

 fleep of plants, to the abfence of light. Hill's Sleep of 

 Plants, and the Caufe of Motion in the Senfuive Plant ex- 

 plained, i2mo. 



SEN 



Mr. Ellis has de fcribed a fenfitive plant, which is a TiatiTe 

 of tiiL- fwamps in North Carolina, called dionsa mu/cipula, or 

 Venus' s fy-trap, (feeDiON^A,) and which, from his ac- 

 count of It, appears to be the moll animated of the whole 

 fenfitive tribe of vegetables. Its fenfibility exids in iu 

 leaves, each of which exhibits, in miniature, the figure of a 

 rat-trap with ttcth clofing on every fly or other infeft that it 

 tempted to talle the fweet liquor which is fuppofed to be 

 fecreted in certain minute red glands that cover its inner fur- 

 face ; but before it has had time to talle it, the lobes of the 

 leaves rife up, and inclofe and grafp the invader, and he is 

 foon deprived of his life by the aftion of three (mall ereft 

 fpines, fixed near the middle of each lobe ; nor do the leave* 

 open again while the dead animal continues there. The 

 fame efFeft is produced by a (Iraw or pin. 



Mr. Ellis conjeftures, that in the conftruftion and motive 

 powers of this plant, nature may have had fome view to Jt» 

 nouri(hment, by forming the upper joint of each leaf like a 

 machine to catch food, and by having laid a bait upon the 

 middle of it, to entice the unhappy infeft that becomes it* 

 prey. But, perhaps, it may be equally probable, that 

 nature has armed and animated this plant for the prefervation 

 of its juices againd the depredation of infefts. Ellis's Di- 

 reftions for bringing over Seeds and Plants, &c. 1770. 

 Sensitive Plant, Bajlard. See jEscuyno.mene. 

 Sensitive Poiver. See Mental Philosophy. 

 Sensitive or Senfible fiid, the foul of brutes, or that 

 which man is fuppofed to have in common with brutes. 

 See Brute. 



It is thus called, either as intimating its utmod faculty to 

 be that of fenfation ; or, perhap?, becaufe it is fuppofed to 

 be material, and to come under our fenfes. 



Lord Bacon all'erts, that the fenfible or brute foul is 

 plainly no more than a corporeal fubllance, attenuated by 

 heat, and thus rendered indivifible ; or a kind of aura or 

 vapour, partly of an aerial, and partly of a fiery nature, en- 

 dued with the foftnefii of air, to be fit to receive imprelTions, 

 and with the vigour of fire to communicate its aftion ; fed 

 partly with oily matters, and partly with aqueous ones in- 

 clofed in the body, and, in the more perfeft animals, prin- 

 cipally in the head, moving along the nerves, and reftored 

 and repaired by the fpirituous blood of the arteries. Bac. 

 de Augment. Scient. lib. v. See Life. 



SENSKOWA, in Geography, a town of Pruflia, in the 

 palatinate of Culm ; 15 miles N.E. of Thorn. 



SENSORIUM, in Phyfwlogy, the part which feels and 

 perceives, the common centre, to wliich fenfations are con- 

 veyed, and from which volition emanates ; in other words, 

 the brain. In medical and phyfiological writings, this ex- 

 pre(rion is ufed as fynonimous with brain ; thus we read of 

 affeftions of the fenforium ; of fenforial power and influence, 

 &c. Senforium commune, is the imaginary point of the 

 brain, the refidence of the metaphyfical foul, to which 

 every fenfation is brought, and from which all determi- 

 nations of the will proceed. The fpeculations on this fub- 

 jeft have been founded in the aflumed unity of the foul. 

 Phyfiologically fpeaking, there is not the flighted ground 

 for fuppofing fuch a part to exid in the brain. Our re- 

 marks on the funftions of the brain and parts connefted with 

 it, will be found under the articles Brain, Life, and Ner- 

 vors Syjlem. See alfo Mental Philosophy. 



Sir Ilaac Newton confiders the univerfe as the fenforiuia 

 of the godhead. 



SENTELIUS, Lodovicus, in Biography, a difciple of 

 Henry Ifaac, and in 1530 appointed chapel-mader to the 

 duke of Bavaria. Many of his compofitions are inferted in 

 the Dodecachordon of Glareanus, with great encomiums. 



He 



