CAN 



[ 169 ] 



CAN 



ture of one less fertile, or even of drift- 

 sand. If there be an excess of branches, 

 the saw and the priming-knife must be 

 gradually applied. It must be only a 

 tree of very weak vital powers, such as is 

 the golden pippin, that will bear the 

 general cutting of the annual shoots. A 

 vigorous variety would exhaust itself the 

 following year in the production of fresh 

 wood. Nothing beyond a general rule 

 for the pruning can be laid down. Keep 

 a considerable vacancy between every 

 "branch, both above and beneath it, and 

 especially provide that not even two twigs 

 shall chafe against each other. The 

 greaterthe intensity of light, and the freer 

 the circulation of air amongst the foliage 

 of the tree, the better the chance for its 

 healthy vegetation. If the disease being 

 in a fruit-tree be a consequence of old 

 age, it is probably premature, and in- 

 duced by injudicious management ; for 

 very few of our varieties are of an age 

 that insure to them decrepitude. We 

 have never yet known a tree, unless in 

 the last stage of decay, that could not 

 be greatly restored by giving it more air 

 and light, by careful heading in pruning, 

 improvement of the soil, and cleansing 

 the bark. 



If the soil, by its ungenial character, 

 induces the diseases, the obvious and 

 only remedy is its amelioration ; and, if 

 the sub-soil is the cause of the mischief, 

 the roots must be prevented striking 

 into it. In all cases it is the best prac- 

 tice to remove the tap-root. If the trees 

 are planted shallow, as they ought to be, 

 and the surface kept duly fertile, there is 

 not much danger of the roots striking 

 into the worst pasturage of the sub-soil. 



Scrubbing the bark of the stem and 

 branches with a mixture of soapsuds and 

 urine, and, where any pruning has taken 

 place, keeping the wounds covered with a 

 mixture of clay and cow-dung, are the 

 best local applications. We once thought 

 resinous plasters the best; but subsequent 

 experiments have altered our opinion. 



The canker in the auricula is a rapidly- 

 spreading ulcer, which, destroying the 

 whole texture of the plant where it oc- 

 curs, prevents the rise of the sap. Some 

 gardeners believe it to be infectious, and 

 therefore destroy the specimen in which 

 it occurs, unless it be very valuable ; but 

 this we believe to be erroneous, the reason 

 of the disease appearing to be infectious, 

 or epidemic, being, that it occurs to 



many when they are subjected to the 

 injurious treatment. 



It appears to be caused by the appli- 

 cation of too much water, especially if 

 combined with super-abundant nourish- 

 ment. Therefore, although cutting out 

 the decaying part, when it first appears, 

 and applying to the wound some finely- 

 powdered charcoal, will effect a cure, if 

 the disease has not penetrated too deeply, 

 yet it will be liable to return immediately, 

 if a less forcing mode of culture be not 

 adopted. No auricula will suffer from 

 this disease if it be shifted annually, and 

 the tap-root at the time of moving be 

 shortened, a thorough system of draining 

 being adopted, and excessive damp during 

 the winter being prevented by proper 

 shelter. 



Parsley, grown in a poor soil, is also 

 liable to canker in the winter. Mr. Barnes 

 says he never found any application which 

 eradicated this disease so effectually as a 

 mixture, in equal parts, of soot and 

 slacked lime thrown over the plants. 

 The cure is complete in a few days, the 

 vigour of the plants restored, indicating 

 that this species of ulceration arises 

 from deficient nourishment. 



The tubers of the potato, also, are 

 liable to the speck, black spot, or canker, 

 a disease which we once thought occa- 

 sioned by the calcareous earth, lime, or 

 chalk contained by the soil ; but, on more 

 lengthened observation, we find it in all 

 soils, and in seasons characterized by 

 opposite extremes of wetness and dryness. 

 Hence we are induced to consider that 

 the disease arises from some defect in 

 the sets employed, or to potatoes being 

 grown too often on the same site. It is 

 quite certain, that in ground tired of pota- 

 toes, the disease most extensively appears. 

 This suggests that it is occasioned by a 

 deficiency of some constituent in the 

 soil, a suggestion confirmed by the fact, 

 that in the fields of the market-gardeners 

 near London, which are supplied without 

 stint with the most fertilizing manure, 

 this disease of the potato is comparatively 

 unknown. 



The stems of succulent plants, such 

 as the cacti, mesembryanthemums, and 

 the balsam, as well as the fruit of the 

 cucumber and melon, and the stalk of 

 the grape, are all liable to canker in some 

 form. 



CA'NNA. Indian Shot. (The Celtic 

 name for a cane, or reed. Nat ord., 



