168 



CHEMICAL CONSTITUTION 



[BOOK ii. 



appear to differ materially. The lowest of this series Schleiden 

 regards as sugar, the highest as the perfect cell-membrane. The 

 members of this supposed series are described as becoming 

 more and more insoluble in water as they ascend the scale. " 

 M. Payen selected with the utmost care the nascent tissue 

 of the ovules of the Almond, Apple, and Sunflower; the 

 half-formed tissue of the Cucumber; the sap of the same 

 plant; the two months' old pith of the Elder; the pith of 

 J^schynomene paludosa ; the hairs of Cotton ; and the new 

 tissue of spongioles. They gave him the following results : 



But when he came to analyse wood in which a deposit had 

 taken place, he found these proportions materially altered ; 

 the numbers being 



When, however, the tissue was acted upon by such agents 

 as have the property of destroying the matter of lignification, 

 the proportions of the three fundamental principles ap- 

 proached more nearly those of primitive tissue. 



