CH. v.] THE SAP. 179 



same or of a neighbouring tree, may be inarched to 

 the denuded portion of the branch, and the fruit will 

 then proceed to maturity. Mr. Knight's experiment 

 was tried upon a peach tree, the fruit of which he 

 was anxious to taste, but which produced that season 

 only two peaches, and from the branch bearing which 

 all the leaves had fallen. 



Cuttings for multiplying any individual may in 

 general be taken either from the stem, branch, or 

 root, and are, in fact, grafts, which by being placed in 

 the earth, a medium favourable to the production 

 of roots, expend their juices in the formation of ra- 

 dicles instead of aiding the stock to effect that 

 developement of vessels necessary for their union 

 to it had they been grafted. A due degree of mois- 

 ture in the soil is all that is absolutely required 

 from it by cuttings, for these will often produce 

 roots if placed in water only. The time for taldng 

 off cuttings from the parent plant for propaga- 

 tion, is when the sap is in full acti\'ity, the vital 

 energy in all its parts is then most potent for the 

 developement of the new organs their altered circum- 

 stances require. Well-matured buds are foimd to 

 emit roots most successfully, and apparently for the 

 same reason that they are least liable to failure when 

 employed for budding, viz., that being less easily 

 excitable, they do not begin to develope until the 

 cutting has the power to afford a due supply of sap. 



n2 



