424? The Rev. J. B. Reade on the Chemical Composition 



Objections to the foregoing Statement, copied from the Report of 

 the Proceedings of the Association given in " TheAthenccum" 

 September 16. 



" Professor Henslow observed that in his work he had al- 

 luded to the great difficulty of isolating entirely either mem- 

 brane or fibre. The cells of the cellular tissue must contain 

 some fluid matter in their interior, besides the fibre that lined 

 them externally [? internally]. Mr. Rigg had experimented 

 on spiral vessels which contained both membrane and fibre; 

 therefore the ultimate composition of membrane and fibre was 

 still a desideratum. Professor Lindley said it was important 

 that facts of this kind should be well made out. As a proof 

 of want of care in the paper, it might be inferred, from the 

 author's statements, that there were no spiral vessels in the 

 petals of the hyacinth ; but the fact is, they are very abun- 

 dant. It appeared to him that the author had mistaken cel- 

 lular tissue and woody fibre, for the elementary membrane 

 and fibre, the chemical analysis of which was so difficult." 



Reply to the above Objections. 



To Professor Lindley. 

 Sir, Peckham, Sept. 18, 1837. 



I find from the Report of the proceedings of the " British 

 Association " which appeared in " The Atheneeum" on the 

 16th instant, that my short notice of the chemical composition 

 of vegetable membrane and fibre was met by Professor Hen- 

 slow and yourself with three objections, which it will be in- 

 cumbent upon me to remove before you can possibly attach 

 any value to the facts which were adduced. I therefore trust 

 that you will have the goodness to allow me to lay before you, 

 by letter, that reply which my absence from Liverpool pre- 

 vented me from making on the spot. 



Following the arrangement adopted by Professor Henslow 

 in his " Principles of Botany*," it may be stated that the two 

 elementary textures of plants are membrane and fibre; of these 

 materials the two elementary organs, viz. cells and tubes, are 

 constructed ; and of these organs, the two elementary tissues, 

 viz. the cellular tissue and the vascular tissue, are respectively 

 composed. 



It is first of all necessary to inquire how membrane and 

 fibre are employed in the construction of the elementary 

 organs ; whether they invariably occur conjointly in each of 

 the two kinds of organs, or whether these organs are respect- 

 ively composed of the one or the other only. 



* Cabinet Cyclopaedia, Henslow's Principles of Botany, pp. 13,14. 



