ON INCREASING THE SIZE AND NUMBER OF TUBERS. 375 
to the subject. There is nothing more annoying to the person who has 
the charge of a collection of valuable stove-plants than the attacks of 
insects, which, from their small size, are scarcely visible, and, from 
their great numbers, unconquerable. The want of an effectual and 
easily-applied remedy, which, while innoxious to the plants, would 
destroy or banish the vermin, is severely felt in some large establish¬ 
ments, as many curious plants are lost, or preserved with difficulty, 
only in consequence of insects ( Psyllidce , Thripidce , Aphidai, and 
Coccidce ) seating themselves upon them, and in such nooks and corners 
as no brush or topical labour whatever can dislodge. Such plants are. 
Cacti, Mammalaria, and some of the Aloes. No remedy but such as are 
liquid, vapourous, or as powder, can reach the retreats of these little 
plagues; and, therefore, some such remedy is a desideratum requiring 
the attention of every one engaged in the cultivation of plants. 
On increasing the Size and Numbers of Tubers, &c.— 
It was long since made known by the President of the Horticultural 
Society of London, that, by divesting potato plants of their flowers and 
fruit, the tubers would be increased both in size and numbers. This 
was a very rational suggestion of the worthy President, and quite con' 
sistent with the laws of the vegetable kingdom. The grand purpose 
of every plant is to increase itself by seeds, by offsets, or by tuberous 
processes proceeding from the roots, which also may be called offsets, as 
in fact they are. A great majority of plants reproduce themselves by 
seed only ; many by suckers or offsets, and also by seeds; and a third 
description perpetuate themselves by offsets, living germs on the stems 
or leaves, and at the same time by seeds also. 
Now by long experience it has been found that, if plants be pre¬ 
vented from producing progeny in any particular way to which they 
are naturally prone, they will make a stronger effort to increase them¬ 
selves by some other way. If, for instance, a bulb be prevented 
flowering and ripening seed, it will certainly produce an increased 
number of offsets; and, contrariwise, were it prevented from produc¬ 
ing offsets by repeated examination to destroy them, the seeds would 
be thereby much increased, and sooner matured. 
This law of nature may be taken advantage of in many more ways, 
in bringing about practical results, perhaps, than have yet been thought 
of. We were very much pleased, some time ago, to hear how the 
senior Mr. Harrison (at Petworth we think it was) took advantage of 
this law of vegetation, to increase and enlarge the tubers of the Oxalis 
crenata. His experienced eye seeing that the tendency of the plant, 
in our moist climate, was to run too much £C to straw,” wisely con- 
