370 
POPULAR SCIENCE REVIEW. 
it is not made sufficiently clear whether ripe fruit only, or ripe 
fruit containing ripe seeds capable of germinating, are de- 
veloped — a very important element to be considered, as the 
fruit may often ripen and develop only imperfect seed or none 
at all. 
The structural changes hitherto effected as a consequence of 
man’s interference, either intentionally or of necessity, are 
relatively slight. Consider, for instance, the artificial condi- 
tions under which plants are transplanted, pruned, grown, fed in 
gardens, and then contrast the rare instances in which any abso- 
lute or essential changes in structure (not merely of degree of 
development, more or less) occur. Important structural changes 
of a relatively permanent character appear, as a rule, to be 
brought about very slowly and gradually. 
As regards functional activity, however, the case is very 
different. Very slight alterations will often immediately and 
profoundly modify the fertility of a given flower and the vigour 
of its seedlings. Cases are recorded wherein a flower ordinarily 
sterile, when fertilised by its own pollen, has developed perfect 
fruit and seeds when grafted on to some other species. Culti- 
vation, climatic changes, diseases, injuries, all have a tendency 
to influence for good or ill the reproductive functions of plants, 
even though the change in circumstances be apparently slight, 
and the structural alteration consequent on them absolutely 
inappreciable. 
We have already cited instances where altered climatal con- 
ditions, as the transfer of a plant from Europe to America, 
have, on the other hand, induced changes in the sexual organi- 
sation of the plant. There are several cases cited where a 
species growing within certain latitudes is of one sex chiefly, 
while the same species growing in other latitudes developes 
mainly flowers of the opposite sex. Instances of a similar 
character are related in reference to moisture. A willow 
growing in a very wet locality has been known to produce 
female flowers only, while in a dry place male catkins only were 
produced. In the case of some Begonias, which, under ordi- 
nary circumstances, produce separate male and female flowers 
on the same plant, Mr. Anderson Henry has succeeded in 
inducing the formation of female flowers only by removing 
two out of the three stigmatic lobes, and fertilising the 
remaining one. All the plants, four or five in number, which 
have resulted from this cross, have produced female flowers 
only. Mr. Henry has repeated the experiment with the same 
result. Such observations as these need confirmation and 
extension ; and from the ease with which they may be made, 
and their importance, may be commended to the special notice of 
amateurs. It is obvious also that in the case of ordinarily 
