Sect. II. 2. 



ABSORBENT VESSELS. 



II 



i 



b 





Befidesthefe abforbents in the roots of plants there are others, which 

 open their mouths on 



bforb the moiftu 



f th 



■nal furfaces of the bark and leaves to 

 rnofphere, refembling the cutaneous 



lymphatics of aninaal bodies; the exiftence of thefe is (liewn, becaufe 

 a leaf plucked ofFand laid with its under fide on water will not wither 

 fo foon as if left in the dry air. 

 branch, which is feparated from a 



The fame if 



bark 



f 



be kept moift with w 



A third branch of abforbent veflels opens its mouths on the internal 

 furfaces of the cells and cavities of the vegetable fyftem to abforb the 

 fecreted fluids, after they have performed their adapted offices, fimilar 

 to the cellular lymphatics of animal bodies, as may be lliewn by 

 moiflening the alburnum or fap-wood, and the internal furface of the 

 bark of a branch detached from a tree, which will not then fo foon 

 wither as if left in the dry air unmoiftened. 



Another means of demonftrating the abforbent powers of the parts 

 of vegetables is by inferting them into glafs tubes, or into tall narrow 

 veffels filled with water, and obferving how much more rapidly the 

 furface of the water fubfides than in fimilar veffels by evaporation 



alone. 



i 



2. By the following experiment thefe vegetable abforbent veffels 

 were made agreeably vifible by a common magnifying glafs. I placed 

 in the fummer of 1781 fome twigs of a fig-tree with leaves on them 

 about an inch deep in a decodion of madder (Rubia tin6l), and others 

 in a decodion of logwood (hasrnatoxylum campechenfe), along witb 

 fome fprigs cut off from a plant of piciis* Thefe plants were chofen 

 becaufe their blood is white. After fome hours, and on the next 

 day, on taking out either of thefe, and cutting 



off from 



bottom 



about an eighth of an inch of the flalk, an internal circle of red points 

 appeared, which i believed to be the ends of abforbent veffels coloured 



red 



ith the decod 



and which probably exiflcd in the 



formed alburnum, or fap-wood, while an external ring of arteries w 



C 



feen 



