CUTTINGS. 71 



tissue is less absorbent than when younger, and 

 that they are less likely to suffer from either 

 repletion or evaporation. 



For to gorge tissue with food, before leaves 

 are in action to decompose and assimilate it, is 

 as prejudicial as to empty tissue by the action 

 of leaves, before spongioles are prepared to 

 replenish it. 



For this reason pure silex, in which no stim- 

 ulating substances are contained (silver sand,) 

 is the best adapted for promoting the rooting of 

 cuttings that strike with difficulty. 



And for the same reason cuttings with what 

 gardeners call a heel to them, or a piece of 

 the older wood, strike root more readily than 

 such as are not so protected. The greater 

 age of the tissue of the heel renders it less 

 absorbent than tissue that is altogether newly 

 formed. 



It is to avoid the bad effect of evaporation 

 that a proportion of the leaves are usually re- 

 moved from a cutting, when it is first pre- 

 pared. 



The method of striking cuttings in double 

 pots, the outer filled with earth in which the 

 cuttings are placed with the ends inserted in 

 the earth touching the sides of the inner one, 



