BOOK OF FRUITS. 19 



same spurs will continue to produce fruit for 

 a great length of time ; but they do not often 

 produce fruit until they have a surface of 

 branches very large in proportion to the sap 

 supplied by the roots. Thus we find that 

 when pear trees are planted in a deep, rich 

 soil, they grow rapidly, and therefore require 

 a number of years to bring them to a bearing 

 state ; on the contrary, when growing in a 

 light or dry shallow soil, they collect but a 

 small quantity of sap, and require but a confin- 

 ed surface which is produced in a short time, 

 and they are consequently brought to a bear- 

 ing state in a few years. Wherever canker 

 or gum appears, the decayed or infected part 

 must be cut entirely out, and some soot mois- 

 tened and rubbed over the wound, or the com- 

 position hereafter named. This will generally 

 prevent its spreading further, and save the 

 branch. 



With regard to what is called Fire-blight, 

 which occasionally effects the pear tree, during 

 the months of June and July, causing the 

 branch to turn black and its leaves to wither, 

 and which may sometimes^ caused by forcing 

 or high manuring, or to the duration of the van- 



