BY .lAMKS M. PETRIE. 851 



Method of Extraction. 



The plants were air-fhned, and then tlie leaves were separated, 

 crushed, and afterwaids fhu^ly powdered. Of this air-dried leaf- 

 powder, 2' 5 kilos, corresponding- to about 1 1 -5 kilos, of fresh 

 leaves, were extracted with f<()% alcohol. The extraction was 

 continued until almost complete; and the alcoholic fluid, measur- 

 ing 31 litres, was distilled under diminished pressure, and at a 

 temperature not exceeding .'^)0 C. The distillation was continued 

 till the residue was free from alcohol, and C(mcentrated to a thick 

 syrup. This viscous residue was treated with warm water, 

 filtered through calico, and the residue washed until no more \vas 

 dissoh ed. There was collected on the cloth-filter a black, sticky 

 mass, consisting mostl}' of chlorophyll and resins, and weighing, 

 when dried, 200gms., or 8% of the air-dried leaves. The aqueous 

 filtrate, aftei* standing in tall cylinders for a few days, deposited 

 a considerable quantity of brown, amoi-phous resin. The lattei' 

 was removed and washed with cold watei*. 



The opaque, dark brown solution was next purified by the 

 addition (1) of an equal volume of 10% lead acetate solution, 

 and (2) of an excess of basic lead acetate, after removing the 

 previous bulky deposit. These very voluminous yellow precipi- 

 tates were separated by spinning in the centrifuge, and were 

 washed in the same manner with cold water, and reserved. Next, 

 the solution was made free from lead by saturation with hydrogen 

 sulphide, and the precipitate removed and well washed. 



The aqueous solution, measuring 18 litres, was now concen- 

 trated by distillation at a low temperature, to a volume of about 

 2 litres. At this stage, the solution was thoroughly extracted 

 by shaking out with ether, and in this wa}^ the free acetic acid 

 was removed. 



Crystallisation. 

 Two volumes of strong alcohol were then added to the solution, 

 and, on standing to settle, a dark syrupy deposit formed, from 

 which the solution was decanted. The latter was then concen- 

 trated by evaporation to a viscous mass, and on the addition of 

 95% alcohol to this residue, an insoluble viscous substance re- 



