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XXXII. Phytological Errors and Admonitions. By the Rev. 

 Patrick Keith, F.L.S.* 



HPHE profound research, the acute discrimination, and the 

 ■*■ eloquent expression of facts, of arguments, or of opinions 

 displayed in the writings of M. De Candolle, have obtained 

 for their author a high and well-merited reputation, whether 

 as a botanist or phytologist; so much so, that we shall not 

 err if we apply to him the well-known maxim of Horace, 

 which says, 



Cui lecta potenter erit res, 



Nee facundia deseret hunc, nee lucidus ordo. 



De Art. Poet. 40. 



I had been repeatedly led to make this application of the 

 maxim in perusing different portions of his Physiologie Vege- 

 tate; but especially in a late perusal of the Considerations 

 Preliminaires which he affixes to that work, and in which he 

 presents to the notice of the reader a succinct and correct 

 view of the true principles of phytological investigation, mark- 

 ing specifically the path to be pursued and the errors to be 

 avoided. The structure of the several organs of vegetables, 

 as in a state of rest, is the first branch of the study of the 

 phytologist— that is, the anatomy of the plant ; their agency 

 in the ceconomy of vegetation is the second — that is, the study 

 of the forces with which the organs act, or by which they are 

 acted upon. In the former case we are to explore with the 

 most rigid scrupulosity their hidden and internal structure ; 

 in the latter, we are not to ascribe to the vital energies of the 

 plant effects that are merely tissual on the one hand, or 

 chemical on the other ; nor to its tissual or chemical properties, 

 effects that are merely vital ; but we are to be careful to assign 

 to every effect its true and proper cause f. 



Here we have, doubtless, the golden rule of all phytologi- 

 cal investigation. Yet the investigator can make use of it 

 only according to the best of his ability ; and in the difficulty 

 of accounting satisfactorily for the various phaenomena of ve- 

 getation, it is not surprising that phytologists should have been 

 occasionally seduced into error, and led to assign effects to 

 wrong causes. The grand stone of stumbling is to be met 

 with in accounting for those effects which are evidently vital, 

 and in which the life of the vegetable seems to approximate 

 closely to that of the animal. This is the respect that has led 

 phytologists to overstep the limits which bound the legitimate 

 scope of vegetable investigation, and to ascribe to vegetables 

 faculties, the existence of which is at best but extremely du- 

 bious. Tissual susceptibilities did not seem to them sufficient 



* Communicated by the Author. f Phys, I'cgct., torn, i. p. 6. 



