VEGETABLE SAP. 121 



practical observation, disqualifies us from either as- 

 senting- to, or denying- what can only be a plausible 

 supposition. It is also said that flowers and fruit are 

 formed from accumulations of elaborated sap. For 

 instance, if a tree, or a branch only be " ringed," the 

 matured sap thereby pent up and prevented from 

 sinking to the lower parts, is expended in the pro- 

 duction of flowers and fruit ; thus attributing to the 

 sap the property of conversion into organs. Were 

 it only inferred that perfect juice is necessary to the 

 sustentation and expansion of flowers and fruit, the 

 idea would be reasonable ; but that organic structure 

 can be spontaneously formed from a mere fluid is 

 wholly incredible. 



The foregoing observations concerning the pro- 

 perties and motions of vegetable sap, being very 

 diiferent from the usual notions entertained of it, 

 the writer hopes to be excused if he occupies another 

 page or two of remarks, by way of justification of 

 himself for thus differing so much from the opinions 

 of his cotemporaries and professional brethren on 

 this important part of vegetable physiology. A full 

 explanation is the more necessary on his part, because 

 the belief of the annual descent of the sap is not 

 only, as before observed, a very old idea, but also 

 because it serves to explain several circumstances 

 occurring in the growth of plants, which cannot be 

 otherwise accounted for. The writer does not deny 

 the possibility of occasional or partial sinkings of the 

 sap ; on the contrary, he is fully convinced of its 



