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30 PRINCIPLES OF BOTANY, ETC. 
we 
from this isolated observation, founded as it is in 
truth, attempt to deny in all animals the existence 
of a difference of sex ? Since Gleditsch first, in a bo- 
tanic garden, impregnated the Chamaerops humilis, 
which is a female plant, with pollen of the male 
plant, which Koelreuter sent to him from Karls- 
ruhe, and obtained ripe seeds and young plants, 
which before never had been possible, thousands of 
similar experiments have been made which put it 
beyond doubt, that two sexes exist in plants. Every 
person may indeed easily convince himself of the 
fact, by repeating such experiments on the species 
of melon and gourd, and everywhere in the vege- 
table kingdom, he will find two distinct sexes. 
G29 5e , 
Each seed, as we know, (§ 288), already exists 
in the germen during the time of blooming, before 
fecundation takes place, and contains a very clear 
liquor, called by Malpighi the Chorion. With this, 
most likely, the fecundating particle of the male 
semen become mixed, and thus produce the em- 
bryo of the new plant. Koelreuter, on the con- 
trary, thinks that the moisture of the stigma; which 
he, according to his favourite idea of an oily, im- 
pregnating fluid of vegetables, supposes likewise to 
be of the nature of oil, becomes mixed with the 
fluid of the male, and that these two combined, are 
conveyed into the seed. However, though this may 
be true, many other changes take place in the seed — 
sooner or later after fecundation. For in the neigh- 
bourhood of the navel a smal! vesicle appears, filled 
with 
