430 



subject for introduction to the western coasts of the British 

 Islands, and may also prove to be of value commercially since the 

 local supply is becoming exhausted and plantations do not appear 

 to have been started in America. 



In order to test whether the bark of an English-grown tree 

 would yield the drug in the same percentage and of as good a 

 quality as that of the native samples, one of the Kew trees of 

 about the size of the one shown in the plate was cut down for 

 purposes of analysis. 



Messrs, Burroughs, Wellcome & Co. very kindly undertook to 

 examine the bark and to report the results of their investigation, 

 and 5j£ lbs. of dry bark, the produce of the Kew tree, was sent in 

 February last to Dr. H. A. D. Jowett, senior chemist of the 

 Wellcome Research Laboratories, London, for analysis. 



The bark sent was duly worked up into tabloids — some of which 

 are now in Museum No. I — and it has been reported that " the 

 present extract is undistinguishable in its action from that made 

 from American Bark," and in a further letter from Messrs. 

 Burroughs, Wellcome & Co., it is stated that " The physician, to 

 whom your special Cascara was submitted, reported it to be equal 

 to the average of tabloid products from bark grown in America." 



Chemistry. 



With 



is still somewhat confused and unsatisfactory. The history of the 

 subject has been ably dealt with by Dr. Jowett, who has also 

 lone a great deal of work in attempting to discover the active 

 principle of the drug. The following account has been extracted 

 from the paper to which reference has been made. 



The only definite principle which has been certainly isolated 

 from Cascara bark is emodin, and in addition a small amount of a 

 substance isomeric with emodin, melting at 183° C, but insoluble 

 in ammonia. Glucose has also been found, and a substance 

 which, on treatment with acids, yields syringic acid. 



The bark contains about 2 per cent, of a fat yielding the alcohol 

 rhamnol, which is identical with the alcohol obtained from 

 K6-sain seeds (Brucea mmatrana, Roxb.). 



All attempts to obtain the bitter principle, an unpleasant and 

 characteristic feature of Cascara bark, or derivates of it in a 

 crystalline form were unsuccessful. 



No difference could be observed between the chemical 



(3 years old). - 



(1 year old) or of the so-called mature 



Beyond slight differences in the amounts of extractive, &c, the 



identical results. 



i/i 



Physiological experiments which were made for the purpose of 

 locating the active principle of the drug, showed that emodin is not 

 the active principle and exerts very little influence, if any, on the 

 cha id nstic action of Cascara. The active principle or principles 

 producing the aperient action of the drug are contained in that 



