Br, Bell on the FhyfioUgy of Plants. 413 



tioned, it is of a fimilar ftruftnre in all plants, 

 Thefe are the folid parts of vegetables. 



But there are likewife fluids, or juices in 

 vegetables : and thefe are of two kinds. The 

 one is of the fame nature in all the variety of 

 vegetables: the other varies according to the 

 different plants in which it exifts. The former, 

 which is called tht Juccus communis, when col- 

 leded early in the fpring, from an incifion made 

 in the birch or vine, differs little from com- 

 mon water.* The Litter, which is named the 

 fuccus p-oprius, pofftffcs V2.110US properties in va- 

 rious plants, and gives to each its fenfible qua- 

 lities. Thefe two juices never mingle with each 

 other in the tree, and the latter is found in the 

 vqfa propria only. 



It is not yet afcertained, whether the juices 

 of plants are tranfmitted through veffeis, or 

 cellular fubftance. Each fide of the quellioa 

 has had its advocates, who have fupported 

 their refpedive opinions with probable argu- 

 ments : but it is to be regretted, that, on fo 



• It has, however, been alledged to contain a faccha- 

 rine matter in feme trees, a^ in the maple, &c. It has 

 likewife been fuppofed to contain an acid- But, in vari- 

 ous experiments which Dr. Bell made on it, he found 

 nothing in it of either kind ; and therefore, where fnch 

 appearances have taken place, he fuppofed them to arife 

 from an adventitious mixture of the fap, and the fuccus 

 proprius. J. C 



interefting 



