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[ 39!) 



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torpidity in the action of the root ; and 

 this, perhaps, at the very period when the 

 greatest demand is made upon it to sus- 

 tain the excessive perspiration which is 

 going on in the leaf, and to furnish fresh 

 matter for elaboration, to both which 

 ends it is frequently quite inadequate, 

 owing to drenching rains. If the young 

 fibre be examined at such inclement pe- 

 riods, it will be found somewhat disco- 

 loured, and, in some cases, quite rotten. 

 Shanking, we conceive, is generally caused 

 by the unnatural disagreement of tem- 

 perature between the root and top, inde- 

 pendent, in the main, of the question of 

 moisture. It generally occurs with vines 

 which have been somewhat forced ; sel- 

 dom on open walls seldom with vines 

 forced in pots or tubs. The obvious 

 prevention of shanking is securing a 

 congenial relative temperature to the 

 roots and foliage. 



Rust comes upon the berries in the 

 form of a rough, rusty appearance of 

 their skins, which have, in fact, become 

 thick and indurated. Some think it arises 

 from their being handled, or the hair of 

 the head touching them ; but the disease 

 is often too general to admit of this 

 topical explanation. We believe it to 

 arise from an over-heating of the vinery, 

 however unintentional, whilst the grapes 

 were young, and thus tending to force 

 them to a premature rapidity of growth. 

 Any excessive pressure upon the cuticle, 

 whether from within or from without, 

 causes its thickening. This considerable 

 elevation being succeeded by a sudden 

 reduction of temperature, will almost 

 certainly induce the disease. 



The Spot affecting the berries seems to 

 be the same disease as shanking, only 

 affecting a different part. Like this dis- 

 ease, it is a gangrene, and is probably oc- 

 casioned by an irregularity in the supply 

 of moisture and vicissitudes of tempera- 

 ture, but especially if one of the extremes 

 is much below the degree of heat most 

 favourable to the healthy growth of that 

 plant. Muscats are particularly liable to 

 the spot. Our opinion that sudden vi- 

 cissitudes of temperature are the causes 

 ' >f this disease, seems to be well sustained 

 l>y the fact, that the parts nearest the 

 glass, that is, the upper portions of the 

 bunches, and those parts most exposed 

 to the sun's influence, are the first to 

 suffer; and this, also, goes far towards 

 substantiating the assertion, that the 



shade of the foliage is necessary to the 

 well-doing of grapes. 



Want oj Colour is often a defect of the 

 Black Grape, but not at all necessarily 

 arising from deficient light The green 

 colour of leaves depends entirely upon 

 the presence either of light or of uncom- 

 bined hydrogen gas ; but vegetable reds, 

 purples, and other colouring matters of 

 fruits are formed, though less intense, 

 even in a total absence from light. So 

 far from full exposure to light being 

 requisite for the full colouring and ripen- 

 j ing of grapes, they never attain these 

 desired qualities so well as when shaded 

 by one thickness of leaf. ' The colouring 

 matter of all fruit is dependent partly 

 upon the leaves immediately above it, and 

 partly upon the fruit itself, the necessary 

 digestion of the sap being commenced 

 in the one and perfected in the other. 

 If this digestion or elaboration of the 

 sap is checked by ungenial temperature, 

 but more particularly if the crop is too 

 heavy for the vine, or if the leaves, es- 

 pecially above the bunches, are too much 

 thinned, defect of colour will be the very 

 usual consequence to the berries. We 

 have seen the blackest of berries in situ- 

 ations where the sun had never shone 

 on them since they blossomed ; indeed, 

 it only requires a little close observation 

 for one season to dispel such a fallacy. 

 It sometimes, however, happens, that the 

 principle leaves on the same shoot with 

 the bunch are shaded by other main 

 leaves, or by laterals. Such shading is 

 sure to be prejudicial to the colouring of 

 the berry, as well as to the maturation of 

 the buds connected with the shaded leaves. 

 And here we have one of the reasons for 

 such close stopping as the vine is sub- 

 jected to. Over-cropping alone will lead to 

 bad colouring ; indeed, is one of the most 

 fruitful sources of it. It exhausts the 

 tree of every r partic]e of prepared sap, 

 and produces debility in the root, which 

 renders it readily susceptible to the stag- 

 nating rains of an unpropitious season. 



In order to promote good colouring, 

 the ripening process should not be hur- 

 ried. It is evident that very high tem- 

 peratures are not required for this pur- 

 pose, for the Black Hamburgh, on com- 

 mon walls, is not deficient in colour, in a 

 good season. Now, the colouring process, 

 in the latter case, occurs in the end of 

 September, when the temperature ^ at 

 nightmust sometimes be near the freezing 



