8o CLASSICS OF MODERN SCIENCE 

 siderable time exposed in vain, to the access of the male pollen. 



Afterwards, when these virgin plants began to decay through age, 

 I examined all their calyces in the presence of several botanists and 

 found them large and flourishing, although every one of the seed-buds 

 was brown, compressed, membranaceous, and dry, not exhibiting any 

 appearance of cotyledons or pulp. Hence I am perfectly convinced 

 that the circumstance which authors have recorded, of the female 

 hemp having produced seeds, although deprived of the male, could 

 only have happened by means of pollen brought by the wind from 

 some distant place. No experiment can be more easily performed 

 than the above ; none more satisfactory in demonstrating the genera- 

 tion of plants. 



The Clutia tenella was in like manner kept growing in my window 

 during the months of June and July. The male plant was in one 

 pot, the female in another. The latter abounded with fruit, not one 

 of its flowers proving abortive. I removed the two pots into different 

 windows of the same apartment ; still all the female flowers continued 

 to become fruitful. At length I took away the male entirely, leav- 

 ing the female alone, and cutting off all the flowers which it had 

 already borne. Every day new ones appeared from the axila of 

 every leaf ; each remained eight or ten days, after which their 

 foot stalks turning yellow, they fell barren to the ground. A 

 botanical friend, who had amused himself with observing this phenom- 

 enon with me, persuaded me to bring, from the stove in the garden, 

 a single male flower, which he placed over one of the female ones, 

 then in perfection, tying a piece of red silk around its pistillum. 

 The next day the male flower was taken away, and this single seed- 

 bud remained, and bore fruit. Afterwards I took another male 

 flower out of the same stove, and with a pair of slender forceps 

 pinched off one of its antherse, which I afterwards gently scratched 

 with a feather, so that a very small portion of its pollen was discharged 

 upon one of the three stigmata of a female flower, the other two 

 stigmata being covered with paper. This fruit likewise attained its 

 due size, and on being cut transversely, exhibited one cell filled with 

 a large seed, and the other two empty. The rest of the flowers, being 

 unimpregnated, faded and fell off. This experiment may be per- 

 formed with as little trouble as the former. 



The Datisca cannabina came up in my garden from seed ten years 



