ON THE PRUNING OF VINES. 79 



important preliminary remark, namely : that the old 

 wood of a vine, or that which has previously bore fruit, 

 is not only of no further use at any subsequent period, 

 but is a positive injury to the fertility of the plant. The 

 truth of this remark depends on the fact, that every 

 branch of a vine that produces no foliage, appropriates 

 for its own support a portion of the juices of the plant 

 that is generated by those branches that do produce fo- 

 liage. To prove this fact, and to make it as clear as 

 possible, it will be necessary to describe, briefly, and in 

 part, the process by which the life of a vine is sustained, 

 and its parts annually nourished. 



The first movement of the sap in the spring takes 

 place in the branches, and lastly in the roots. The 

 buds, in consequence of the increasing temperature of 

 the air, first swell, and attract the sap in their vicinity. 

 This fluid having lain dormant, or nearly so, throughout 

 the preceding winter, becomes gradually expanded by 

 the influence of the solar rays, and supplies the buds 

 with nourishment from the parts immediately below 

 them. The vessels which yield this supply, becom- 

 ing in consequence exhausted, are quickly filled by 

 fluid from the parts below them, and in this manner the 

 motion continues until it reaches the roots, the grand 

 reservoir of the sap ; by which time the solar heat hav- 

 ing penetrated the soil, the roots begin to feel its enli- 

 vening influence. The whole body of sap then begins 

 to move upwards, and as soon as the quantity propelled is 

 more than sufficient to distend all the vessels in the stem 

 and the branches, the buds begin to elongate and unfold. 

 This takes place in general about the vernal equinox. 

 From this time the fluid becoming more expanded eve- 

 ry hour, its ascent is simultaneously increased in force 

 and velocity. The vessels in the branches being filled 

 to repletion, the buds quickly open, and shoots and 

 leaves rupidly protrude. The beginning of May ar- 



