I 



F 



d 



1 



I 



Sect. II. 4. 



ABSORBENT VESSELS. 



13 



with uniform fuccefs, and it is fo eafily made by haftily apply 

 common lens after the divifion of a vinc-ftalk, that I think then 



be 



and 



wonderful that thefe veflels, which 



found in the alburnum, and confifl: of a fpiral line, whether they may 



conlifl of both 



properly be called abforbent or umbilical vefTcls, 01 

 fhould ever have been fuppofed to be air-veffels. 



There is neverthelefs an experiment by Dr. Hales, which would 

 at firft view countenance the affertion, that vegetables abforb 

 cemented the lower end of a fmall tvi^ig of a tree 



He 



with 



o-lafs tube about four inch 



to> 



and fet the other end of th 



tube an inch deep in water, and obferved in a little time, that the water 

 rofe an inch in the tube; but this muft happen from the vegetable 



veffels emptying themfelves by the afcent of their juices, and hj 



5, a portion of the air 



ri^id 



and therefore not contradin 



wa 



the above 



forced into them by the prefTure of the atmofphere, as in 

 obfervation on the vine-branch cut horizontally. 



This reception of air does not happen to the veflels of animal bo- 

 dies, when they are emptied of their blood, owing to the lefs rigidity 

 of their coats; whence the weight of the atmofpheric air prefles 



fides too-eth 



a 



d clofes the veflc 



{lead of palling into it. 



In the fame manner no air would pafs into the veflels of the lungs of 



mals 



fp 



nlefs the preflure of the atmofphere on th 



fides was prevented by the adion of the mufcles, which enlarge th 

 cavity of the thorax by elevating the ribs. 



4 



There are neverthelefs certain horizontal veflels of large d 



probably 



hich pafs through the bark of trees to the alburnum, which 

 ;ontain air, as they are apparently empty, I believe, in the 



^ .„^etabl 



o 



for the bark of trees confifts of longitudinal fibres 



b 



which are joined together, and appear to inofculate at certain difl:an 



d recede from each other bet 



thofe diftances like the mefli 



of a net, in which fpaces feveral horizontal apertures are feen to pe- 

 netrate through the bark to the alburnum, according to Malpighi, 



I who 



V 



