EXTRACTS — HORTICULTURE. 661 
wounds heal more rapidly from above dgwuwards than in any other way ; uo 
doubt stimulated by returning juices. The most serious wounds of the bark, are 
those which detach it to a great extent all round the stem, for the conse- 
quence is, that all branches beyond the wound, are forced to become fruitful, and 
thus premature decay is brought on. Simple incised wounds, and even those in 
which the bark is raised from the stem to a considerable extent, may unite if the 
edges be accurately adapted to each other, and the whole covered with some 
plaster to exclude the air : Forsyth's preparation is perhaps one of the best. In 
pruning, numerous wounds are unavoidably inflicted ; these, however, when 
smoothly aud properly made, produce no mischief. Stems bi-uised or fractured 
more than half through, in many cases will recover ; but when more than that it 
ii generally better to remove them at once, especially in old plants. There ars 
many plants which never recover even slight fractures, but gradually decay. On 
the other hand, many succulent stems will, by proper management recover, after 
being bruised and broken to a great extent. The most proper treatment for frac- 
tured or braised stems, is to tie them up, bringing the edges of the wound neatly 
together so as to promote a union, and covering the whole with some plaster. 
Wounds of Stems from Insects. — There is a minute insect, which fre- 
quently infests the stems of apple and pear-trees ; it is probably the Coccus ar- 
borum described by Reaumur. It attacks all the stems indiscriminately, which, 
in consequence, becomes covered with numerous muscle-like bodies, varying in 
length from one-eighth to three-sixteenths of an inch. The trees sufier from 
these when numerous by their inducing disease in the bark, from the lodgement 
of water, which they cause, and also by hindering the functions of the bark. 
The most etfectual remedies for this affection that we have tried, are boiling wa- 
ter, as recommended by Mr. Beattie in the memoirs of the Hort. Soc. of £din 
burgh, for 1827, and the "Cream of Lime" applied with care to the stems j or 
they may be scraped off, and the stems afterwards well washed with lime-water. 
Many insects attack the woody parts of plants, and trees in consequence become 
hollow, sometimes, again, the larvae of some insects curiously undermine the 
bark of various trees, living upon the liber and alburnum, and forming twisted 
paths running in all directions. — 
Ulcerations of Stems or "Canker." — So various and opposite are the opi- 
nions advanced concerning the cause of this disease, that it is difficult, if not al- 
most impossible, to discover the real one of eleven authors ; the following table 
will show the various causes, and the number of supporters mentioned by each : — 
Supporters. 
8 Wounds of bark and wood. 
8 Bad soil and subsoil, viz. wet, — stiff clayey — cold clayey 
— cold wet — wet gravel — exhausted soils — mossy bottom. 
4 Injudicious pruning. 
3 Bruises. 
2 Gangrene of young shoots. 
2 Attacks of insects. 
2 Cold wet seasons. 
2 Improper aspects. 
I Load of fruit. 
I Frost injuring sap. 
I Friction. 
