P.4RTS OF TREES FIMT IMPAIRED BY ACE. 277 



different periods communicated accounts to you, supported 

 by the i'dnta previously ascertained by other naturalists, 

 scarcely leave any reasonable grounds of doubt, that the 

 sap of trees* circulates, as far as is aj)pareritly necessary to, 

 or consisteiii with their state of existence und j^rowth. 



The roots of trees, particularly iho&e in coppices, which No deficiency 

 are felled at stated periods, continue so long to produce, occastonrihe 

 and i'vkid, a succession of branches, that no experiments deaiy of trcci. 

 were wanted to satisfy me, thai it is not any defective action 

 of the root, which occasions the debility und diseases of old 

 varieties of the apple and pear tree; and indeed experience 

 every where shows, that a young seeiliing stock does not give 

 the character of youth to the inserted bud or graft. I, how- Plants from 

 ever, procured plants frona cuttings of some very old va- yning<; c.f 



• • /. 1 . .-1 1. • 1 , old varienes of 



rieties of the apple, which readily emit roots; and these the apple 



plants at the end of two years were grafted, about two ©""^f^ed. 

 inches above the ground, with a new and very luxuriant 

 variety of the same species. These grafts grew vei-y freely, 

 and the roots themselves, at the end of four or five years, 

 probably contained at least ten times as much alburnum, 

 as they would have contained, had the trees remained un* 

 grafted. The roots were al<jo free from any appearance of 

 disease, or defect. 



Some crab-stocks were at the same time grafted with th€ Golden pippin 

 golden pippin, in a soil where the wood of that variety L'T-fted on il^f^, 

 rarely lived more than two years : and i again grafted the crab on the '^ 

 annual shoots of the golden pippin with cuttings of a ^.'■^^*. °^ ^*^® jjl 

 young nnd healthy crab^tree, so as to include a portion of '^'^^^"* 

 the wood of the golden pippin between the roots and 

 branches of the native uncultivated species, or crab tree; 

 and in this situation it grew just as well as the wood of 

 the stocV and branches. Some branches also of the golden with other ex- 

 pippin trees, which I mentioned in my former communi- periments, 

 cation of 1795, being much cankered, were cut otf a foot 

 above the junction of the grafts to the stocks; and were 

 regrafted with a new and healthy variety. Parts of the 

 wood of the golden pippin, in which were many cankered 

 spots, were thus placed between the newly inserted g\;afts,. 

 and the stocks; and these parts have subsequently become 

 perfectly free from disease, and the wounds, previously 



made 



