24O AMERICAN VINES. 



of a scion or the upper extremity of a stock planted under 

 these conditions. We see, therefore, that grafts made when 

 the stock has not begun to bleed will have the best chances 

 of success. 



Later on, when the bleeding is already abundant, the 

 success may be quite as great, for the channels conveying 

 the sap become closed at their extremity by gum or bacterial 

 colonies (we have, in fact, all observed that after a few days 

 the section of a cane or spur does not allow the sap to flow, 

 and that a new section made about y* inch below it bleeds 

 abundantly) ; if this moment coincides with the start of growth 

 of both scion and stock, or, better, precedes it, knitting 

 tissue forms easily, and the knitting takes place. But if 

 (and this is the case for late grafts made in April or May, 

 according to the district) the scion starts growing before the 

 flow of sap has ceased, the slightest check in its develop- 

 ment, due to change of temperature or to active evaporation, 

 compromises the strike, the knitting tissue not having been 

 able to form to guard against that check in the growth. 



Finally, still later on, when the vine has ceased to bleed, 

 in June for instance, the knitting takes place under better 

 conditions. 



This explains the beneficial effect of cutting the rooted 

 stocks a few days previous to grafting; the fatal influence 

 of heavy rains during the period of grafting maintaining the 

 grafts in too damp surroundings ; of the too great compact- 

 ness of the soil placed around the joint preventing the escape 

 of excess of sap; and it explains also the good strike often 

 obtained in grafting growing stocks in cold regions of the 

 south-west, centre, and east of France, and also in certain 

 seasons in the south. 



For the knitting tissue to be produced with certainty at 

 the moment the scion starts to grow, or, better, a little be- 

 fore, the surfaces in contact must not be in too damp 

 surroundings; this result may be obtained at any time by 

 cutting the growing stock previously, so as to only proceed 

 with the grafting when the vine has ceased to bleed. 



(&) Operation of Grafting. The stocks, whatever their age 

 may be, are previously decapitated, the soil is removed 

 from around the stump to facilitate the operation. They are 

 decapitated by a section made perpendicular to their axis, 

 generally a little above ground, at the time when the graft 

 has to be done, or, better, a week or a fortnight before, 



