76 On saline combinations 



From this simple but very instructive experiment, we may 

 deduce some highly interesting conclusions. First ; — let us 

 recollect that the fragment of epidermis, prior to its incinera- 

 tion, was digested in a dilute acid, for the purpose of remov- 

 ing all saline matters soluble in that menstruum ; the acid 

 however could not dissolve that portion of saline matter which 

 existed in an organized form, and constituted the fixed skele- 

 ton of the vegetable tissue, because this was completely enve- 

 loped and enclosed on every side by organic matter, over 

 which the dilute acid employed, exercised no solvent action. 

 Next, we learn, that as the outline of every form of tissue is 

 met with, in the saline matter found in its ashes after incine- 

 ration, simply organic matter, or matter destructible by heat, 

 cannot be regarded as forming the true skeleton of plants, but 

 that this skeleton, like that of any animal, consists chiefly of 

 saline, or, (to use the generally received, but evidently impro- 

 per term), inorganic matter. These facts, if shewn to be uni- 

 versally true, are of the highest importance, and will serve to 

 give new and interesting features to the structure of organic 

 tissue ; and even in the present imperfect state of our know- 

 ledge on this head, they cast some little light upon the pre- 

 viously most mysterious subject of the fossilization of wood; 

 and although they are at present quite unequal to the task of 

 explaining this curious process, yet they assist in raising, to 

 a certain extent, the veil of obscurity with which it was co- 

 vered. One of the most puzzling questions that was ever 

 presented to the mind of the naturalist, is the manner in which 

 all, even the minutest and most delicate portions of vegetable 

 tissue, are preserved in a silicified state. It was formerly 

 conceived to be necessary, that in proportion as the minutest 

 atom of a vessel or cell, was removed by decomposition, an 

 equally minute atom of siliceous matter should be deposit- 

 ed from its solution, to supply the place of the organic mole- 

 cule, in order to preserve so perfectly the delicate vessels and 

 cells which are visible in fossil wood ; thus making the pro- 

 cess, which can scarcely be considered otherwise than one of 

 decomposition and destruction of vegetable matter, analogous 

 to that of secretion and absorption in animals, and so placing 

 it on a level with a process which, for its perfection, requires 

 the highest efforts of vital chemistry. Having proved, how- 

 ever, that the skeleton of the most elaborate and delicate form 

 of organic tissue consists of inorganic particles, it is no longer 

 a matter of surprise, that these should be spared when decom- 

 position of organic matter goes on ; or that when by the action 

 of running water or otherwise, every fragment of organic mat- 

 ter is removed, the indestructible materials which compose the 



