162 CHEMICAL CONSTITUTION [BOOK n. 



CHAPTER III. 



OF THE CHEMICAL CONSTITUTION OF THE ELEMENTARY 

 ORGANS. 



THE tissue of plants, as it is first generated, and before it is 

 incrusted with the peculiar secretions formed by the leaves, 

 consists exclusively of oxygen, hydrogen, and carbon : and it 

 is probable that none of the kinds of tissue differ originally in 

 their proportions of these three principles ; for the microscope 

 does not show a difference in the action of chemical agents 

 upon them. 



I mention this because Mr. Rigg has arrived at a different 

 conclusion, the accuracy of which has been insisted upon by 

 the Rev. J. B. Reade, in a paper printed in Taylor's Magazine 

 (Nov. 1837). It must be, however, apparent to any person 

 conversant with vegetable anatomy, that such a separation of 

 tissue as in Mr. Rigg's case is supposed to have been obtained 

 is physically impossible, and, consequently, the results given 

 are fallacious. 



The subject has been subsequently taken up by Schleiden 

 and Payen, whose experiments, made independently of each 

 other, and in entirely different ways, both lead to the conclu- 

 sion that the original tissue of plants is in all cases of the 

 same chemical constitution, or nearly so, but that the sedi- 

 mentary deposit, whether sclerogen, or other matter, formed 

 inside each sac of tissue is of some other chemical nature ; 

 the lignine of chemists is therefore composed of two or more 

 different substances, viz. the primitive tissue and its subse- 

 quent incrustations. As this subject is important with refer- 

 ence to many phenomena in vegetable physiology, I give at 

 some length the results of both Schleiden and Payen. 



The former makes a statement in Wiegman's Archives to 

 the following effect : 



