310 PEINCirLES OF GARDENING. [CH. IX. 



The phenomena of that power — which is justly 

 called vegetable life — have been traced in pre^'ious 

 pages from germination through all the stages of 

 growth, the developement of parts, the circulation 

 of the sap, the mysteries of the impregnation 

 and the matuiing of the fruit; and we will noAT 

 trace the phenomena of the plant's decline and final 

 decay. 



The first symptom of that decline is a deficiency 

 of the usual annual developement of parts. A perma- 

 nently lessened production of shoots, or leaves, or 

 fruit — or of all these — becomes apparent ; and this 

 non-production arises from a diminished power in 

 the roots to imbibe, and of the vessels of the stem 

 and branches to impel, the sap. 



Thus Hales always found that the two, three, and 

 foul' years' old branches of trees imbibed water with 

 much greater force than those of greater age ; and 

 that young A-igorous vines usually exuded their sap 

 with much oreater force than the older and less 



o 



robust. So I have found that our annuals, such as 

 the dwarf kidney bean, mignionette, clarkias, and 

 others, imbibed water with more than twofold ra- 

 pidity when in full bloom, than other plants of the 

 same species and size did in the autumn, though 

 they were still growing and verdant. 



Now, w^hat is the cause of this deficient power — 

 this decline of vigour ? — To me there appears little 



