H 



ABSORBENT VESSELS. 



Sect. II. 5. 



F 



has dven a figure of them, which is copied in Plate T. Fig. 2. of 



k 



Ve 



ry 



fi 



perforations through 



th 



bark 



Q 



f 



trees are alfo mentioned by Duhamel, which be beUeves to be per- 

 fpiratory or excretory organs, but adds, that there are others of much 



larger diameter, fome round and fo 



d which in the bi 



ftand prominent, and pierce the cuticle or exterior bark 

 fique des arbres, T. i.Tab. III. Fig. 8. and 1 1. 



Thefe veflels probably contain air during the living ftate oft 



Phy 



they pierce th 



bark, which frequently confifts of 



y 



doubles, like a roll of linen cloth 



as 



Hyp 



ears in the figure of a walking cane given by 



duced beneath the old one, like a new fcarf-fkin beneath a bhfter in 

 animal bodies ; and the old one fometimes continues, and fometimes 

 peels off like the cuticle of a ferpent, as is feen on the trunks of many 

 cherry-trees and birches. Thefe vefTels, when contra£led in dry tim- 

 ber, appear like horizontal infertions in many planed boards, in 

 which the fplral abforbent veiTels become by their contradion the lon- 

 gitudinal fibres, as app 

 Dr. Grew, Tab. XX. 



Thefe horizontal vefi!els I fuppofe to contain air inclofed in a thin 

 mpift membrane, which may ferve the purpofe of oxygenating the 



fluid in the extremities of fome fine arteries of the embryon buds, in 

 the' fame manner as the air at the broad end of the e^g is believed to 

 oxygenate the fluids in the terminations of the placental vefTels of the 



•-1 



embryon chick, as further noticed in Seift. 111. 2. 6. and III. i. 4. 



5. The abforbent veffels of trees in paffing down their trunks 

 confift of long hollow cylinders, whofe fides I believe to be compofed 

 of a fpiral line, and are of fuch large diameters in fome vegetables as to 

 be vifible to the naked eye, when they become dry and empty, as in 



Air will rapidly pafs through thefe vefTels in either diredion, 

 as may be (e^n in lighting a cane fome inches long at either end, and 

 drawing the fmoke through the pores of it into the mouth, as throuo-h 



cane. 



o 



9, tobacco-pipe. Dr. Hales readily pafled both air and water through 



a recent 



