Botanical Society of Edinburgh. 209 



the efficiency of the scales was not attributable to them as a 

 consequence of their organization and the arrangement of their 

 cells, but that the cells of the effective scales were lined or 

 coated with a doubly-refractive substance, removable by acids. 

 Not only, as above noticed, is this statement of the want of 

 action in the scales of the Olive incorrect, but the second state- 

 ment, that acids remove the efficiency of the scales of ElcEognus, 

 is only correct in the most limited degree, and is explicable in a 

 different way from that in which Ehrenberg viewed it. Even 

 twelve hours^ maceration of these scales in fuming nitric acid or 

 hydrochloric acid exerts no influence upon them, while sulphuric 

 acid in a short time weakens the property in question extremely, 

 without however fully destroying it. As to the cause of this, 

 microscopic examination of the scales treated in this way leaves 

 no doubt, since it demonstrates that the sulphuric acid dissolves 

 the secondary lamellse of the cells, and reduces the cell-membrane 

 to an excessively thin pellicle. Consequently these scales can- 

 not be adduced in evidence to prove that cellulose does not 

 possess, independently and in itself, the property of double 

 refraction. This renders superfluous any discussion of the 

 hypothesis appended by Ehrenberg, that this unknown substance 

 lining the cells may be crystallized. 



It might be conjectured that the remarkably active effect 

 which the epidermal cells of Equisetum hyemale exert upon 

 polarized light, is to be ascribed to the deposition of abundance 

 of silica in the substance of their cell-membranes. But this 

 conjecture finds no confirmation in the circumstance that the 

 effect of these membranes upon polarized light is exceedingly 

 weakened when their organic substance is destroyed by heating 

 to redness. However, this operation does not entirely destroy 

 this action, neither does it in the Diatomese, in which, contrary 

 to the statement of Ehrenberg, lately confirmed by J. W. Bailey 

 (Quarterly Journal of Microscopic Science, 1856, p. 303), many 

 forms, namely various species of Navicula, Synedra, but espe- 

 cially of Pleurosigma, and Melosira arenana, were found by me 

 to be decidedly doubly-refractive. 



[To be continued.] 



PROCEEDINGS OF LEARNED SOCIETIES. 



BOTANICAL SOCIETY OF EDINBURGH, 



January 14, 1858. — Dr. Seller, President, in the Chair.. 



The following papers were read : — 



1. *'0n the Occurrence of a new Muscarl on Mount Ida," bv 

 Dr. John Kirk. 



In April 1 85(5, the author and two other medical officers of the 

 Ann. b; Mag. N. Hist. Ser. 3. Vol.'i. 14 



