900 
ooo 
manner, brought wild Fig-trees in contact with those they cultivated, supposing 
the effect would be the same; but in the Fig the male and female organs are 
both present. The earlier ripening of their fruit resulting from this practice 
was caused by the puncture of an insect brought with the wild Fig from the 
woods, not to the fertilization of the seed as in the case of the Date Palm. But 
no sooner was the important fact discovered that all flowering plants have sex¬ 
ual organs, that most have the two sexes united in the same flower, and that a 
j'mited number have the two sexes, as in the Date Palm, on two separate plants, 
than men were able to take a comprehensive view of the whole subject, to un¬ 
derstand why the barren flowers of the Date Palm were required to fertilize 
the seeds of the fruit-bearing plant, and that the same means were required to 
fertilize the seeds and to obtain perfect fruit of all other unisexual plants. A 
•knowledge of general principles is not only useful as explaining successful prac¬ 
tice and preventing us from making mistakes by endeavoring to accomplish 
•certain objects by means opposed to the laws of nature, but it is especially val¬ 
uable as suggestive of further improvement. A knowledge of the sexes of 
plants, for instance, led to the important inquiry whether by removing the 
stamens of a flower before they had reached maturity, its embryo seeds might 
not be fertilized by the stamens of another nearly allied plant; and if so, whether 
we might not, as in the animal kingdom, blend the good properties of the two 
parents in the offspring, and thus effect a more rapid improvement of useful 
an d ornamental plants than by the ordinary method of selection through suc¬ 
cessive generations; when tested experimentally, this proved to he the case; and 
he, who I believe first turned this knowledge to a practical account, Andrew 
Knight, has been gathered to his fathers but a few years, yet how marvellous 
and how rapid has been the improvement already effected in some plants by 
this means! How great was the power of man acquired over nature by this 
simple interpretation of nature’s laws! 
I have considered it advisable, in the first place, to give a very brief outline 
of the structure of the organs of plants, considering that by this means their 
functions and uses may be better understood. In compiling this essay, I have 
consulted the works on general botany and physiology, of Knight, Lindley, 
Henfrey, Grey and Balfour; and Johnston, Liebig and Solly’s works on agri¬ 
cultural chemistry. Much useful information has also been derived from Lind- 
iey’s Gardeners’ Chronicle, Downing’s Horticulturist, and other periodicals and 
works on farming. 
