121 



ing Juice is the eflicieiit and proximate means employed by 

 nature, for the support and nomishment of every part ; 

 therefore, to say that a tree is vigorous and healthy, is to say 

 in effect, that it has an abundant supply of sap.* 



The true constitution and anatomy of plants was first 

 systematically brought forward, on the continent, by Mal- 

 pighi. Grew, as it is on all hands admitted, made his phy- 

 tological discoveries about the same time, without any com- 

 munication with the ItaUan physician ;t and both, without 

 doubt, felt the impulse which had been given to the spirit of 

 philosophical inquiry, by the genius of Bacon, who showed, 

 how analytical and inductive investigation might be applied, 

 in order to explain the phenomena of vegetable life. In the 

 end of the seventeenth century, while these two eminent 

 men flourished, vegetable physiology was still in its infancy 

 in Europe : but in process of time, as that interesting science 

 attracted the notice of the learned, their theory was confirmed 

 by new facts, and more extended microscopical observation. 

 To Grew and Malpighi succeeded various writers of different 

 nations in the same track, De la Baisse, Hales, Bonnet, Du 

 Hamel, Senebier, and others ; until Hedwig, Willdenow, and 

 especially Dr. Kieser of Jena, and Messrs. Knight, Ellis, and 

 Keith, in our times, have by their ingenious labours thrown 

 the fullest hght upon the subject. 



But the circulation of the sap is not a doctrine that has 

 been universally adopted by phytologists, however reasonable 

 it may seem from the analogy, which we see in other in- 

 stances to subsist between the animal and vegetable king- 

 doms. About the middle of the last century it appears to 

 have fallen into disrepute. Du Hamel refuted it with con- 



* See Grew and Malpighi, Anat. Plant, passim. — Darwin's Phyto* 

 logia. — De Saussure, Encyclop. Method. — Willdenow, Prin. of Bot. 

 p. 85.— Knight, Philosoph. Trans. 1803, 1806.— Ellis, in Art. Veget. 

 Physiol, in Supp. to the Encyclop. Britan. 



tJ>J0TE I, 



16 



