By Thomas Andrew Knight, Esq, 387 



Parkinson also, who lived in the reign of Elizabeth, 

 complains of the unfavourable seasons in the latter part of 

 his life. The grapes did not then ripen as they had formerly 

 done ; or more probably, I believe, he did not find them so 

 sweet as he thought them when he was a schoolboy. That 

 some change may, however, have taken place in our climate, 

 owing to the operation of many concurrent causes, is not im- 

 probable, but not in a degree equivalent to the effects pro- 

 duced. Any considerable change of climate must also have 

 affected alike the new and the old varieties of fruits, and the 

 decay of the latter alone seems therefore to prove some con- 

 stitutional change to have taken place in those. 



If the leaf gradually fail to execute properly its office, a 

 progressive degree of debility, preceding a state of disease 

 and decay, must necessarily follow ; and this I have noticed 

 in some moderately old varieties of the Apple and Pear. 

 They remain free from disease ; they blossom frequently, and 

 sometimes freely; but they rarely afford much fruit; and 

 their recovery, from the exhausted state, in which even a 

 moderate crop of fruit leaves them, is very slow. If this 

 state be induced, as I am well satisfied that it is, by the in- 

 efficient operation of the foliage; it becomes an interesting 

 question at what period of the age of each variety such de- 

 fective operation commences. The observations, which I 

 have had opportunities of making, lead me to believe that it 

 commences at the period when the original tree becomes, 

 according to the ordinary course of nature, debilitated by age ; 

 and I suspect that much the greater part of the varieties of 

 fruit of different species, which are now named m the cata- 

 logues of Nurserymen, have already outlived the periods, at 



