305 



Dr. C. T. Jackson presented the following analysis 

 of the juice of the leaf-stalks of the garden Rhubarb 

 ( Rheum rhaponticum). 



The leaf-stalks, by pressure, yield 90 per cent, of clear juice, 

 and 10 per cent, of cellulose and fibrous matter. 1000 grains of 

 the filtered juice, on evaporation, yield 31 grains of solid extract ; 

 this, burned, leaves 3.3 grains of ashes, or the saline matters of the 

 plant converted mostly into carbonates of the alkali and lime. 



The ashes, analyzed, yielded 



Potash 1.717 



Phosphate of lime 0.350 



Lime 0.002 



Carbonic acid ...... 1.200 



Q 



269 



1000 grains of the filtered juice, analyzed for the acids, saccha- 

 rine matter, and mucilage, gave 



Oxalic acid ....... 3.53 



Malic acid . . . . . . . 7.30 



Glucose or grape sugar . . . . 9.63 



Mucilage . . . . . . . 3.30 



23.76 



The oxalic acid is combined with potash as the binoxalate of 

 potassa, but there is a slight excess of acid over the quantity re- 

 quired for the base. The malic acid, with the exception of the 

 small proportion required for saturation of xtn^tr grains of lime, is 

 in a free state. 



It has long been known that the juice of the rhubarb stalks is 

 the best source from which we can obtain malic acid. This juice 

 has been employed to make an imitation of Champagne wine, but 

 the absence of cream of tartar renders it unfit for that purpose, 

 and the so-called wine is more like cider, the malic being the 

 characteristic acid present. 



Dr. T. M. Brewer presented the following list of the 



PROCEEDINGS B. S. N. H. — VOL. VII. 20 AUGUST, 1860. 



