placed ill contact with a female flower recently open^ and tied this flower with a piece of red 

 silk to know it again. 



The next day I removed the male flower^ and this one germen indeed remained^ and pro- 

 duced fruit. 



After the experiment^ I took another male flower from the stove, and by means of a slender 

 forceps, I removed from it one of its Anthers^ and having scratched it gently with the knib of a 

 pen, I took care that a little oi\t?> farina might fall upon one of the Stigma, having guarded the 

 remaining two stigmata by a cap made by an hollow roll of paper. 



This Germen also grew to a fruit of the ordinary size, and afterwards being transversel}; 

 dissected, it alone produced a large seed in one of the three cells, the other two being empty. 



The other flowers, not having suffered impregnation, every one of them, becoming withered, 

 dropt. 



The repetition of this experiment is also as readily to be repeated as the former. 



FOURTH AND FIFTH EXPERIMENTS. 



' ,- , . , 



The Jatropha Urens {Stmging Jatropha) flowers every year in my hot-house, but the 

 female flowers have preceded the males, and before eight days they lost their petals, and faded, 

 before the male flowers were expanded. 



Hence not only they produced no fruit, but Wi^floivers themselves dropt. 

 Thus it happened that, until the year 1752, we could obtain no fruit of the Jatropha. 



But in this year, the male floioers were in vigour upon a taller tree, at the precise time the 

 females appeared on a small Jatropha growing in a pot. 



This pot I placed under the tree producing male flowers, and in this manner I accomplished, 

 that X]\^ female flowers produced seed, which, being sown in the earth, grew. 



Two years after I placed these male flowers under a piece of paper, until the Farina had 

 fallen upon it, which I preserved rolled up, if I recollect right, for four or ^yq weeks, when 

 this same Jatropha on another branch ^^xodxic^^ female flowers. 



Then I sprinkled that Farina so long preserved in paper upon three flowers, the only ones at 

 that time expanded. 



These three female flowers only hccn,me fruitful, whereas all the other flowers which appeared 

 in the same corymbus fell off abortive.^ 



I have frequently since amused myself by taking the male Farina from one plant, which 

 by sprinkling upon the females of another, I have always found the seeds thereby rendered 

 fruitful. f 



* The same experiment was made on the Jatropha Imperialis (Imperial Jatropha), and with exactly the same result. The male 

 flowers usually occupy the upper part of the plant, and are soon to be distinguished from the females. 



f A similar experiment was made on the Begonia Nitida {oblique -leaved Begonia), which forms one of our Picturesque Botanical 

 coloured plates, where the male and female flowers are very readily distinguished from each other, even at their first appearance, the males 

 having a corolla consisting of four petals, the females of five, which gave the same confirmation of the Sexual Hypothesis. 



« SIXTH 



