THE planter's GUIDE. 



87 



Malpiglii. Grew, as it . is on all hands admitted, made 

 his phjtological discoveries about the same time, without 

 an J communication with the Italian physician ; 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 seven- 

 teenth 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 

 difi'erent nations in the same track — De la Baisse, Hales, 

 Bonnet, Du Hamel, Senebier, and others ; until Hedwig, 

 Wildenow, and especially Dr Kieser of Jena, and Messrs 

 Knight, Ellis, and Keith, in our own times, have by 

 their ingenious labours thrown the fullest light upon the 

 subject. 



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

 been universally adopted by phytologists, however reason- 

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

 instances, to subsist between the animal and vegetable 

 kingdoms. About the middle of the last century it ap- 

 pears to have fallen into disrepute. Du Hamel refuted 

 it with considerable ingenuity ;f and both Du Hamel 

 and Hales, while they generally admitted that the sap 

 both ascends and descends, denied the existence of a cir- 

 culation. Within the last five-and-twenty years, how- 

 ever, the theory has been revived with great lustre, and 

 seems now to be the popular one of the day. In fact, 



* Note I. 



f Phys. des Arbres, lib. v. ch. 2. 



