240 PHYSIOLOGICAL BOTANY. 



yellow, so that they are readily distinguishable from 

 the membrane. The experiments upon the leaves of 

 Allium porrum and the roots of Allium cepa, which have 

 been already detailed, were made by this method. It 

 must be remembered that the starch-granules are here 

 dissolved ; hence, if it be required to observe them, no 

 acid must be used. If this experiment be reversed, and 

 the section be first examined with tincture of iodine, the 

 starch is easily recognised ; but no nitric acid must be 

 added, because it dissolves the iodised substances, leaving 

 the membrane, which cannot now, at least very readily, 

 be recognised and sketched. But by this method the 

 membranes of the utricles, the contents of which are 

 dissolved, are distinctly seen within the cells. Caustic 

 potash and caustic soda also remove the contents of the 

 membranes, and leave the latter, although in an indistinct 

 state. But I must return to Payen's investigations. He 

 next examined, by elementary analysis, the following 

 structures, after having exhausted them with several 

 solvent media. The leaves of Endive and Ailantlms 

 glandulosa, the internal cellular tissue of Agave Ameri- 

 cana, the spiral vessels of Musa Sapientum, the radicles 

 of maize; portions which had resisted the digestive 

 process in animals, the albuminous tissue of maize and 

 corn, the albumen of Phytelephas, and the kernels of the 

 date ; the hairs of the seeds of the Virginian poplar, the 

 vegetable membranes of which the nest of the wasp is 

 constructed ; the heart- wood of the oak, the wood of the 

 Coniferae, also Conferva rivularis and oscillatoria, the 

 membrane of Agaricus edulis, probably Ag. campestris L. 

 He also makes use of the name Scariola, as well as 

 " Chicoree endivie" How can any chemical investiga- 

 tions be of use, if the object which has been examined is 

 not definitely stated? Then follow investigations upon 

 the substances existing in the cells which also contain 

 nitrogen. I have quoted these details here for the pur- 

 pose of introducing a memoir by Fromdery, on Cellulose, 

 given in the ' Scheikundigen Onderzoekingen,' 2 D. s. 

 36, and which is extracted into the ' Journ. f. praktische 



