WOUNDS 265 



especially in Horticulture, the rootless cuttings are placed in 

 a chamber where the air is saturated with moisture. 



Cuttings of the Caspian willow, that appear to have rooted 

 perfectly, frequently die off on sandy soil in the height of 

 summer, or in the autumn of the first year. The reason for this 

 is that in the early part of the season adventitious roots appear 

 both upon the cortex and the callus of the cutting, and when 

 the upper layers of the loose sandy soil dry up the greater 

 portion of the roots on the cortex, most of which are dis- 

 posed horizontally, die off. When this is the case, it often 

 happens in the height of summer that the roots which have 

 originated in the callus of the wound, and which always 

 penetrate the soil obliquely, are unable to supply sufficient 

 water to satisfy the wants of the leafy shoots, which con- 

 sequently wither. On this account the soil of osier-beds should 

 be worked to as great a depth as practicable, so as to encourage 

 the roots to go deep. 



GRAFTING 



A technical discussion of the various operations connected 

 with the transference of a living shoot or bud from one 

 plant to another would be entirely out of place here. It is 

 sufficient that we should shortly consider the internal changes 1 

 that are associated with the process. If we except grafting by 

 approach, where two adjoining plants are so united to each 

 other at one or more places that similar wounds in the cortex 

 of both plants are brought into and retained in intimate con- 

 tact till complete coalescence has taken place, we find that all 

 grafting operations agree as regards the main principles. A 

 portion of a plant provided with buds but destitute of roots, the 

 so-called scion, or only a portion of cortex furnished with a bud 

 (the shield and eye), is united to a rooted plant, called the wild 

 plant or stock, in such a way that when coalescence takes place 

 water and food-materials will be transferred from the stock to 

 the scion, as well as plastic materials from the scion to the 

 stock. 



The operation succeeds, as a rule, only when, on the one 



1 Goppert, Innere Zustdnde der Bciume nach ausscrn Vcrletzungen. 

 Breslau, 1873. 



