Dr. Hancock on Quinine. 309 



in the formidable bowel complaints so common in tropical 

 climates." 



Here is a weight of evidence added to our daily experience 

 in proof of the efficacy of astringents and aromatics, both as 

 febrifuges and as general tonics. 



Now it is vulgarly believed, and indeed we frequently hear 

 it asserted by those who ought to know better, that the sul- 

 phate of quinine contains all the virtues of the bark. A very 

 little reflection, however, must convince any unbiassed mind 

 of the falsity of this opinion. It neither contains the astringent 

 nor the aromatic principle; and a large portion of bitter 

 extractive is also rejected with the infusion, in the process 

 for the manufacture of sulphate of quinine. All these are 

 essential to the entire powers of the bark, as we know 

 from their tonic effect on the system. The resino-extractive 

 matter was considered by Murray as the principle of the 

 greatest activity of any the bark contains. " Astringents," 

 says Dr. Paris, vol. i. p. 152, " are capable of acting as 

 permanent stimulants, of curing intermitting fever, and of 

 obviating states of general debility.' These principles are 

 entirely thrown away in the process — and as to the invaluable 

 antiseptic properties of the bark, the quinine contains nothing 

 of it. 



All this is evident from the methods taken for the preparation 

 of quinine. Of those persons who assert, that the quinine 

 contains all the virtues of the bark, very few, I believe, can 

 have reflected upon the process employed in its preparation. 

 The following one, from the Paris Pharmacopoeia, will serve as 

 an illustration. A tincture of the bark is first made with 

 alcohol, which is evaporated to an extract. This extract is 

 next washed with repeated portions of watery solution of potass, 

 till it ceases to colour the water, and then with pure water to 

 wash away the potass. This residuum then, divested of every- 

 thing soluble in water, together with the agency of potass, is 

 the meagre portion of the bark which remains, and which is now 

 to be digested in an acidulated liquor (acide hydrochlorique). 

 This liquor is next to be filtered, boiled on magnesia, filtered 

 again, and evaporated to dryness. This residue is ultimately 

 to be digested in alcohol, filtered, and the tincture evaporated, 



