126 
REMARKS ON VEGETABLE GROWTH, ETC. 
Among the multifarious phenomena of Vegetation, no circum¬ 
stance is more incomprehensible than that which is so frequently 
seen, namely, two fruit-trees of the same kind, size, and age, 
growing in the same soil and aspect, of which one shall be every 
year (if the season proves favourable) covered with flowers and 
fruit, while the other is as constantly barren of both. We know 
this proceeds from the different habit of the trees : the fertile tree 
from having become once fruitful, continues to be so, as a certain 
consequence ; while the other produces nothing but barren sum¬ 
mer shoots. 
[From what cause does the one at first become fruitful, and how 
does it retain the habit ?—This is bad philosophy.— Con.] 
We have been long acquainted with two St. Germain Pear-trees 
of this character ; both are trained on a west wall, and next to 
each other, at the distance of twenty feet from stem to stem. In 
volume they are very much alike, having both covered their allotted 
spaces of the wall; and both are equal in size and number of branches. 
Had the barren tree been of stronger growth the enigma of its 
yielding no fruit might have been accounted for ; but it does not 
appear that this is the case. 
Perhaps there is some defect in the male parts 'of the blossoms, 
as happens to those of some other sorts of Pears ; and which may 
be remedied by what the late T. A. Knight, Esq. suggested, 
viz. to suspend branches of other sorts, while in flower, over the 
blossoms of the barren tree. The late Mr. Sweet discovered that 
hothouse or greenhouse plants, which flower in winter, and of 
which seeds are required, seldom ripen them if the flowers are not 
impregnated by hand. And this seems a very rational expedient ; 
because in the open air flowers are naturally impregnated either 
by the wind or by honey-seeking insects, whereas, in a house, 
flowers have but little chance of having their pollen blown or 
carried from one to the other, by either wind or insects ; and 
therefore manual assistance is necessary, particularly in stoves. 
But to recur to the barren and fruitful trees of the same kind, 
met with in every garden : it is a fact universally known, that those 
of a luxuriant habit, whether proceeding from too rich or too damp 
a soil, or from too much pruning or cutting-in to keep the head on 
a limited space, never can be abundantly fruitful : and hence the 
