312 STATE #F THE SAP IN WINTER. 



Explanatioa of through the leaf in the preceding year; but that it is gene- 



manner in 



which the juices ratec * Dv a procefs fimilar to that of the germination of feeds, 



of plants circu. and that the fame procefs is always going forward during the 



tudes, changes'" ^P rm g' ant ^ fummer, as long as the tree continues to generate 



*c. new organs. But towards the conclufion of the fummer I 



conceive that the true fap (imply accumulates in the alburnum, 



and thus adds to the fpecific gravity of winter-felled wood, 



and increafes the quantity of its extractive matter. 



I have tome reafons to believe that the true fap defcends 

 through the alburnum as well as through the bark, and I have 

 been informed that it the bark be taken from the trunks of trees 

 in the fpring, and fucli trees be fuffered to grow till the fol- 

 lowing winter, the alburnum acquires a great degree of 

 hardnefs and durability. If fubfequent experiments prove that 

 the true fap defcends through the alburnum, it will be eafy to 

 point out the caufe why trees continue to vegetate after all 

 communication between the leaves and roots, through the bark, 

 has been intercepted: and why fome portion of alburnous 

 matter is in all trees* generated below incillons through the 

 bark. 



It was my intention this year to have troubled you with 

 fome obfervations on the reproduction of the buds and roo's 

 of trees; but as the fubject of the Paper, which I have now 

 the honour to addrefs to you, appeared to be of more im- 

 portance, I have deferred thofe obfervations to a future op- 

 portunity ; and I (hall at prefent only obferve, that I conceive 

 rayfelf to be in pofleflion of facts to prove that both buds and 

 roots originate from the alburnous fubftance of plants, and not, 

 &s is, I believe, generally fuppofed, from the bark. 



I am, &c. 



T. ANDREW KNIGHT. 

 Elton, Dec. 1, 1 804. 



* I have in a former paper ftated that the perpendicular moots of 

 the vine form an exception. I fpoke on the authority of numerous 

 experiments; but they had been made late in the fummer; and on 

 repeating the fame experiments at an earlier period, I found the 

 refult in conformity with my experiments on other trees. 



Singular 



