128 Propagation of Plants by Cuttings. 



The great stimulants of vegetable life are heat, air, light, 

 and moisture ; and in the management of cuttings, these 

 agents require to be regulated with the greatest nicety and 

 precision. The more leaves upon a cutting, or the softer its 

 texture, the more care is necessary, as it is the more liable to 

 suffer, either from excess or deficiency of any one of these 

 agents. For instance — if the cutting is subjected to a high 

 temperature, it will cause an immediate expansion of its buds, 

 and elongation of stem and leaves. Or, if under the influ- 

 ence of an arid atmosphere, the dry air will quickly act upon 

 the moist leaves, exhaust the sap and render them flaccid. 

 The same result will follow, if light be admitted in excess, 

 as it will paralyze the energies of the cutting, by a too rapid 

 decomposition of carbonic acid. Again, if the soil be kept 

 too dry, there will be no accumulation of matter at the base 

 of the cutting, the dry soil absorbing it as fast as produced. 

 On the other hand, if water be administered too copiously, the 

 total destruction of the cutting will rapidly ensue ; if decom- 

 position once commences, it soon communicates its qualities 

 to the whole. 



In this, as in many other horticultural operations, no defi- 

 nite rule can be prescribed, to be equally applicable in every 

 case. Hence, the many contradictory directions often given 

 upon the same subject, which may be either right or wrong, 

 just according to circumstances. There are various methods 

 of modifying the extreme influence of the agents employed in 

 the economy of vegetation. While cuttings are forming 

 roots, the presence of light may be modified by keeping 

 them a sufficient distance from the glass, or by inserting them 

 into a large pot only half filled with soil. A humid atmos- 

 phere is easily maintained by the evaporation of water ; and 

 to prevent saturation in the soil, the pots ought to be well 

 drained. By inverting a small pot inside a larger one, a 

 chamber is formed, which allows a salutary access of air and 

 heat to the base of the cutting ; at the same time affording a 

 ready egress for superfluous moisture. 



It may appear difficult to secure at all times, the exact con- 

 ditions required ; nevertheless, they should be aimed at, and 



