by james si. petrie. 431 



Complete Chemical Examination. 



Extraction . — For the purpose of a detailed investigation of the constituents 

 of the leaves, 6 kilograms of the air-dried plant powder were extracted with 80 % 

 alcohol, by maceration and percolation at room temperature. Three large per- 

 colators were employed. The fresh spirit was addetl to the first, the percolate 

 from this run into the second, and the percolate from the second added to the 

 third, thus making one complete extract. Each complete extract was assayed 

 for total solids contained in it ; in this way the progi-ess of the extraction was 

 ascertained . 



1st extract, 3 litres, contained 285 gms. solid matter. 



246 

 171 

 114 

 ,) <J3 „ 



» 36 „ 



" -4 „ 



28 litres 975 gms. 



The total solid matter, soluble in alcohol, thus obtained, represents 16 % of the 

 air-dried leaf -powder. The 28 litres of alcoholic extract consisted of a dark 

 brown fluid, and were distilled under diminished pressure to a thick syrup. The 

 temperature of distillation did not exceed 40° ('. After removing the solvent in 

 this way there remained in the still a thick, black, tarry product. 



Distillation of the Extract in a Current of Steam . — The semi-solid mass was 

 then distilled in a current of steam, when there was obtained 2.5 litres of 

 aqueous distillate, and in the still an insoluble resinous mass with a large volume 

 of hot aqueous liquid. The latter was filtered hot, the solid portion boiled in 

 ■water, and decanted many times till the washings were colourless. This sub- 

 stance, insoluble in hot water, when dry weighed 392 gms. The filtered solution 

 and washings were set aside to cool, and after a few days a quantity of a lirown 

 solid deposit separated, which was washed with cold water, and when dry weighed 

 64 gms . The following portions were obtained : — 



A. Volatile steam distillate 2.5 litres 



B . Aqueous solution 7 



C. Chlorophyll and insoluble resins 392 gms. 



D. Brown deposit on cooling the aqueous soln. 64 ,, 



The insoluble substances in C and D. weighing 456 gms., made up 47 ff of the 

 whole alcoholic extract. 



Examination of the Volatile Portion, A. 



The distillate, measuring 2.5 litres, and showing a distinctly acid reaction to 

 litmus, was shaken out with ether many times. 



( 1 ) . The remaining aqueous fluid was first examined : it was still acid in 

 reaction to litmus. When boiled with Fehling's solution it produced a slight 

 reduction. It also reduced mercuric oxide and silver nitrate when boiled, in- 

 dicating the presence of a small amount of formic acid. A little of the solution 



