431 



portion of the alcoholic extract which is soluble in water and pre- 

 cipitated by lead sub-acetate, and further, it is contained in that 

 portion of the regenerated lead sub-acetate precipitate which is 

 soluble in ethyl acetate. It has not been found possible to isolate 

 a crystalline product from this extract, and therefore no clue has 

 as yet been obtained as to the chemical nature of the active 

 principle.* 



The Tree. 



The native home of R. Purshiana is on the Pacific slope of 



from 



Washin 



# — o > " -— — ~~ — ~tr 0-1/ — 



It is stated to vary considerably in size, in some places forming a 

 shrub of 10-12 feet in height and in others it "becomes a small 

 tree 20-40 feet high with a trunk 1 foot or more in diameter.f 



The average yield of a tree is about 10 lbs. of bark, and as 

 1,000,000 lbs. of the drug are required annually, some 100,000 

 trees have to be destroyed each year ; a shortage of bark was 

 reported in 19054 



The following note, which has been prepared by the Assistant 

 Curator, gives an account of the trees of R. Purshiana in the 

 Royal Botanic Gardens, Kew, one of which is shewn in summer 

 and in winter condition in the accompanying plates. 



The trees of Rhamnus Purshiana which are now growing in 

 the Arboretum at Kew were raised from seed sent by Mr. Luther 

 Burbank in December, 1891. The seeds, which had been 

 collected in Sonoma Co., California, were sown on the 5th of that 

 month and germinated at the beginning of the following March. 

 The largest tree is now 21 feet high, 18 feet in the spread of its 

 branches, and the trunk girths 24 inches. It should be mentioned 

 that they are growing in the ordinary soil of Kew which is 

 shallow and of a dry, sandy nature. Planted in a richer deeper 

 soil, the trees would no doubt have been considerably larger. 

 They usually form low spreading specimens each with a short 

 trunk and a dense head of branches. (The tree shown in the 

 Plates has been stem-pruned, and shows a more upright habit.) 

 The bark is rather distinct and pretty by reason of the numerous 

 short light-coloured fissures that traverse it longitudinally. 



The species is undoubtedly quite hardy at Kew. All our trees 

 passed through the great frosts of February, 1895, unprotected 

 and without injury, and they are not likely to experience a 

 severer test than that. They flower regularly in May, but the fruits, 

 which are ripe in August, are not produced regularly or in any 

 quantity. The fertility of home-grown seeds has not yet been 

 tested, but seeds recently imported from the United States have 

 germinated badly. 



Of the seeds sent by Mr. F. R. S. Balfour only three germinated 

 and all the rest appear to have been bad at the time of sowing. 



i i_^^__m. ■ ■■ " ■ i -* 



• Chemical investigation of Caecara Bark by H. A. D. Jowett. D. Sc. Paper 



x i 7 - The Wellcome Chemical Research Laboratories. 



T Report of the Commissioner of Agriculture, Washington, \8bo, pp. b/, o«s, 



+ - P i ate IIX -i Rhamnug Pun iana. 

 + r'harm. Journ. 1905, p. 323. 



34356 



A 2 



