oration published by Boeehaave, shewed that he knew this thing accurately, although he has 

 not demonstrated it by actual experiments. 



From that period, that is from the year 1718, many have attempted to raise up this rock, 

 especially the author of the Sexual System, who had supposed that the thing itself was clear, 

 and already established from his various labours, although Pontedera* has indeed attempted to 

 refute it. 



stick I gently touched the inside of one of the filaments, which instantly sprung from the petal with considerable force, striking its anthera 

 against the stigma. I repeated the experiment a great number of times ; in each flower touching one filament after another, till the anthers of 

 all six were brought together in the center over the stigma. 



" I took home with me three branches laden with flowers, and placed them in ajar of water, and in the evening tried the experiment on 

 some of these flowers, then standing in my room, with the same success. 



" In order to discover in what particular part of the filaments this irritability resided, I cut ofl" one of the petals with a very fine pair of 

 scissars, so carefully as not to touch the stamen which stood next it : then, with an extremely slender piece of quill I touched the outside of 

 the filament which had been next the petal, stroking it from top to bottom ; but it remained perfectly immoveable. With the same instru- 

 ment I then touched the back of the anthera, then its top, its edges, and at last its inside; still without any eflbct. But the quill being 

 carried from the anthera down the inside of the filament, it no sooner touched that part than the stamen sprung forwards with great vigour 

 to the stigma. This was often repeated with a blunt needle, a fine bristle, a feather, and several other things, which could not possibly in- 

 jure the structure of the part, and always with the same effect. 



" To some of the anthers I applied a pair of scissars, so as to bend their respective filaments with sufficient force to make them touch the 

 stioma ; but this did not produce the proper contraction of the filament. The incurvation remained only so long as the instrument was ap- 

 plied; on its being removed, the stamen returned to the petal by its natural elasticity. But on the scissars being applied to the irritable part, 

 the anthera immediately flew to the stigma, and remained there. A very sudden and smart shock given to any part of a stamen would, 

 however, sometimes have the same effect as touching the irritable part. 



" Hence it is evident, that the motion above described was owing to an high degree of irritability in the side of each filament, next the ger- 

 men, by which, when touched, it contracts, that side becomes shorter than the other, and consequently the filament is bent towards the 

 germen. I could not discover any thing particular in the structure of that or any other part of the filament. 



" This irritability is perceptible in stamina of all ages, and not merely in those which are just about discharging their pollen. In some 

 flowers, which were only so far expanded that they would barely admit a bristle, and whose antherae were not near bursting, the filaments 

 appeared almost as irritable as in flowxrs fully opened; and in several old flowers, some of whose petals with the stamina adhering to 

 them were falling off; the remaining filaments, and even those which were already fallen to the ground, proved full as irritable as any I 



had examined. 



" From some flowers I carefully removed the germen, without touching the filaments, and then applied a bristle to one of them, which 

 immediately contracted, and the stigma being out of its way, it was bent quite over to the opposite side of the flower. 



" Observing the stamina in some flowers which had been irritated returning to their original situations in the hollows of the petals, I found 

 the same thing happened to all of them sooner or later. I then touched some filaments which had perfectly resumed their former stations, 

 and found them contract with as much facility as before. This was repeated three or four times on the same filament. I attempted to stimu- 

 late, in the midst of their progress, some which were returning, but not always with success ; a few of them only were slightly affected by 



the touch. 



" The purpose which this curious contrivance of Nature answers in the private oeconomy of the plant, seems not hard to be discovered. 

 When the stamina stand in their original position, their antheree are effectually sheltered from rain by the concavity of the petals. Thus 

 probably they remain till some insect, coming to extract honey from the base of the flower, thrusts itself between their filaments, 

 and almost unavoidably touches them in the most irritable part : and thus the impregnation of the germen is performed ; and as it is 

 chiefly in fine sunny weather that insects are on the wing, the pollen is also in such weather most fit for the purpose of impregna- 

 tion. 



" The Barberry is not the only plant which exhibits this pheenomenon. The stamina of Cactus Tuna, a kind of Indian Fig, are like- 

 wise very irritable. These stamina are long and slender, standing in great numbers round the inside of the flower. If a quill or feather be 

 drawn through them, they begin in the space of two or three seconds to lie down gently on one side, and in a short time they are all recum- 

 bent at the bottom of the flower." 



* Pontidera was professor of Botany at Pisa, and published, in 1772, his " Anthologia, sive De Floris Natura." " A Discourse on the 

 Nature of Flowers." In his preface he expresses that his chief design in this publication was to repress the prevailing belief of the Sexes of 

 Plants. " Quin etiam cum multos videam praeclare indolis juvenes tum veterum, tum recentiorum potissimum traditionibus ita allici, ut per- 

 facile imperita et infirmiora ingenia in iis ipsis rei Botanicce principiis decipi possint, succurrendum esse, et totis viribus providendum, ne latius 

 malum diducatur, judicavi. Quod sane et illis, quas in horto anno superiore habui, dissertationibus ex parte praestiti, auditores meos subinde 

 monendo, ut ab illis opinionibus, quee ingenii specie blandiuntur, caverent. Perfacile siquidem juvenilis etas inventiunculis, quae novitate 

 alliciunt, capitur, quibus semel imbuta per omne vitce tempus sEepenumero eas servat. Et revera non video quid aliud huic potius timere de- 

 beamus, quam cum homines auctoritate eximia, ut animos rerum imperitos ad se convertant, et alliciant, ita loquuntur: esse stirpes in mares, 

 in foeminas, in androgynas distributas; partesque illas, quas in deliciis habemus, floresque vocamus, nihil aliud esse, nisi generationis organa: 

 dari in plantis, ut Plinii verbis utar. Veneris intellectum, maresque afflatu quodani, et pulvere etiam foiminas maritare ? Quis istos, qui 

 htec se ab aliis non accepisse, sed vidisse profitentur, qui conjugii tempora tradunt, qui rationem, quce frigidce in Venerem stirpes solicitentur, 

 decent, etiamsi iis non omnino assentiatur, tamen non legendos ediscendosque judicabit ? Quo exemplo alii incitati illis sese adjicient. Quare 

 eveniet, ut vel hujusmodi opinionibus sese obnoxios tradant, illisque perpetuo adhsereant, de quibus jam actum esse supra indicavimus; vel 

 ut vanas et commenticias rejiciant, atque una totam rem Botanica in contemptu habeant. His itaque de causis maturandum esse cognovi. 

 Quapropter libellum anno proxime elapso de hujusmodi rebus conscriptum." 



/ - His 



