Dr. Meyen*s Researches in Physiological Botany. 141 



gioles" do not exist. All the analyses show that one may as- 

 sume the proportion of oxygen to hydrogen to be as in water, 

 and that these substances are isomeric (perhaps polymeric, 

 H. C.) with starch, for the small differences found may be 

 considered as faults in the analyses. With regard to these 

 analyses it may be remarked, that however correct they may 

 be, they by no means show us the correct composition of the 

 primitive membrane ; for in the cells of the youngest ova, as 

 well as in those of the cucumber, elder pith, and principally 

 of the root-extremities, indeed, even in the fibres of cotton, 

 there is contained a great quantity of organic substances 

 which cannot be separated without destroying the tender tis- 

 sue, and the presence of these matters renders the analyses of 

 the membrane unsatisfactory. However, we may assume, that 

 by far the greater portion of these substances have an isomeric 

 constitution with starch. Moreover several kinds of wood 

 were analysed in order to show the difference of composition 

 of the primitive membranes of their cells. 



Oak. Box. Aspen. 



T 



i *• > « *■ . < — , 



Initsna- Treated with Natural Treated with Treated once Treated twice 

 tural state. carb. of soda. state. carb. soda, with carb. sod. with carb. sod. 



C ... 54-44 49-68 54-35 49*40 48-00 4771 



H... 6-24 6-02 6-25 6*13 6-40 6-42 



O ... 39-32 44-30 39-50 44-47 45-56 45-87 



From these analyses it certainly appears that in the ligneous 

 substance, besides carbon and water, moreover free hydrogen 

 must be present ; but here it must also be remarked, that it is 

 almost impossible to separate the membrane of the woody 

 cells from their contents, and the microscope shows that va- 

 rious and perhaps resinous substances are contained in them. 

 In a note sent into the Academy on the 24th of December, 

 1838, M. Payen states, that by means of nitric acid he has ex- 

 tracted the incrusting matter of the ligneous cells from the 

 primitive membranes : for this purpose finely rasped oak and 

 box wood were used. The incrusting substance (by which is 

 meant the inner layers of the cellular membrane) dissolved in 

 nitric acid, and was thus separated from the residual tissue, 

 which, after repeated purification, was dried and analysed. 

 The composition was found to be 



C 43-85 



H 5-86 



O 50-28 



whilst the above analyses gave quite a different result. Ac- 

 cording to this then the secondary layers of the cellular mem- 

 brane must exhibit a striking difference in constitution ; but 



