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V. Ansiver to Mr. J. Lindley's Letter on the Subject of Fege- 

 table Phyaiolo^iij*. Bij Sir Jas. Edw. Smith, F.B.S. S^c. 

 President of the LinucEan Society. 



To the Editors of' the Philosophical Magazine cmd Journal. 

 Gentlemen, 

 T CANNOT but respect that independance of character 

 *■ which Mr. J, Lindley avows, in refusing to sacrifice the 

 interests of science to the personal pretensions of any one. 

 I trust that no such sacrifice has ever been looked for on my 

 part ; nor should I honour the man who would offer it. But 

 I do not see how the interests of science are concerned in this 

 gentleman's charge of inaccuracy in my statements. 



My pretensions are simply these — that the theory of vege- 

 tation, first ]5ubHslied in my Introduction to Botany in 1807, 

 is original. Dr. Darwin's experiments and observations first 

 led me to an acquaintance with the true sap-vessels, or 

 arterial and venous system, of Plants, previously taken for 

 their air-vessels and lungs ; and Mr. Knight's more extensive 

 and luminous remai'ks, independent of Dr. Darwin's, but 

 essentially confirming them, led me to reconsider the subject 

 of vegetable physiology. With the theory of Du Humel, to 

 which neither of those writers, nor even Mr. Lindley, adverts, 

 though the only one previously extant, I had always been dis- 

 satisfied ; and while the real sap-vessels remained unknown, 

 the great chemical discoveries of Priestley and others, re- 

 specting the effects of air and light upon the vegetable body, 

 could not be properly understood. But when all these in- 

 quiries and their results were brought together under one 

 view, and the vital principle of my great teacher, Mr. John 

 Hunter, was taken into consideration, it was not difficult to 

 derive from the whole a sufliciently plain and consistent theory 

 of vegetable growth, respiration, secretion, &c. To this Theory 

 I lay claim as original, with the illustration of all the particu- 

 lars concerning the leaves, flowers and fruit, as far as they are 

 dependent upon it, and which had never before been ex- 

 plained, such as the fall of the leaf, but more especially the 

 " flowing of the sap," as it is called, which had occupied so 

 much of the attention of every previous inquirer, without 

 being understood by any one. Whatever obligation I may 

 avow, as I do, to the facts and experiments of others, the 

 theory built upon them is my own, and competent judges 

 have never denied me the credit of it. I am obliged to be 

 thus decisive, because Mr. Lindley has, in a very unworthy 

 iTiauner, attempted to represent me as giving up my own right. 



If 

 * Phil. Mag. vol. Ixiv. p. loH. 



