i6 



THE TROPICAL AGRICULTURIST. 



[July r, 1884. 



Mr. Giles said that he had not doue so. He had over- 

 looked that circumstance when making the comparison, 

 which should have been confined to the relative alkaloidal 

 strength of the pharmacopceial and other liquid extracts. 



Mr. Hadfield said that the method by which Professor 

 Redwood had got at the percentages of the alkaloids con- 

 tained in the liquid extract seemed to him to be rather 

 crude. He thought that a better result would be obtained 

 from the solid extract of which Professor Redwood had 

 spoken, and that the alkaloids of the solid extract would 

 be better represented by previously obtaining an analysis 

 of the bark. Of course this method would involve more 

 trouble. 



Dr. Paul said that in a case of perfect exhaustion the 

 quantity of quinine which ought to be contained in a 

 lluid extract made from a two per cent bark — the minimum 

 laid down in the Pharmacopoeia — would be 35 grains in the 

 fluid ounce. In the case of ten samples which he examined 

 a year ago, however, the total alkaloids only ranged from 

 2 to 10 grains in the fluid ounce, and then the greater part 

 was alkaloid other than quinine. 



Professor Redwood, in reply, said that his object in taking 

 up the subject before the meetiug was to elicit from 

 other people the best means of producing a preparation of 

 bark which had been much extolled by medical men, and 

 most severely criticised and condemned by pharmaceutical 

 speakers in that room. He certainly felt that it would be 

 more becoming on the part of those who had so strongly 

 criticized the liquid extract of bark if they had indicated in 

 what way a preparation having a similar object could be 

 more satisfactorily produced. He had failed to iududce any- 

 body to take the matter up. He had been pleased to find 

 that, in the present discussion, thecriticisms had been rather 

 criticisms of his conduct than criticisms of his paper. He 

 had desired to ascertain the opinion of competent pharm- 

 acists as to the process which he had suggested, but he was 

 told that he stood in a false position. He gathered that he 

 had been looked upon as the author of the rharmacopasia 

 preparation, and he had been asked how he could come and 

 condemn it. The origin of that preparation was well known, 

 and he was not aware that it was at all inconsistent to hold 

 by it until a better was known. That was precisely what 

 he had endeavoured to do on the former occasion. He cert- 

 ainly at that time took exception to Dr. Paul's paper, be- 

 cause there were too many assumptions in it, and it critic- 

 ized a preparation that was not the Pharmacopceia pre- 

 paration at all. Years ago, when he occupied the position 

 which was now held by Dr. Paul, nearly all the barks which 

 came into the London market were regularly analysed by 

 him and reported upon, and therefore he could not fail to 

 be perfectly familiar with the chemistry of the cinchona 

 barks. But all that he had contended for was that in the 

 absence of any better preparation they were justified in 

 holding co that of the Pharmacopceia. Mr. Giles had very 

 fairly commented upon the process described in the paper, 

 but he (Professor Redwood) did not think that Mr. Giles 

 had in any respect damaged his position or shaken his con- 

 clusions. Mr. Giles had not shown a better way by which 

 the valuable constituents of cinchona bark could be taken 

 out; and he (Professor Redwood) gathered from Mr. Giles's 

 statement that his method was the right one. Mr. Giles's 

 strongest objection was that the process described excluded 

 from the finished preparation something which he thought 

 ought to be retained. Upon that point he ( Professor Redwood ) 

 was at issue with him. He did not think it desirable to leave 

 all the extractive matter in the finished preparation. What 

 he did consider desirable was to have a preparation which 

 would dilute with water and form a clear liquid, possess- 

 ing the astringency and the aromatic flavour of good bark. 

 He had obtained this, and he had turned out the red cin- 

 chonic and what he had termed quinovin, a body which 

 Mr. Howard designated as a nauseous bitter which was 

 highly objectionable in the administration of the bark. 

 The liquid extract of the Pharmacopceia and other extracts 

 which professed to resemble it, and even that which was 

 ordered in the United States Pharmacopceia, all possessed 

 the grave defect of throwing down a copious precipitate 

 of a nauseous disagreeable bitter when they were diluted, 

 and this was a substance which he conceived to interfere 

 with the efficacy of the medicine. Mr. Dunstan had made 

 a very proper suggestion with reference to the prepar- 

 ation of a dry extract as well as the liquid extract. He 



(Professor Redwood) had admitted in the paper that per- 

 haps most producers of the liquid extract would not ta Ice 

 the trouble of getting the dry extract first. It had been 

 suggested to him that the dry extract would be found to 

 be highly hygroscopic, and very difficult of preservation. 

 He had endeavoured to satisfy himself on that point, aud 

 he had left some of the solid extract exposed in a dish 

 in his room for a week. The test to which it had been 

 subjected was an exceedingly severe one. He admitted 

 that it attracted moisture and softened, but it is hygro- 

 scopic character was not greater than would be expected 

 in a dry extract of that description. He looked upon this 

 preparation as one which would one day admi t of use in 

 medicine. An infusion or decoction would be bjtter made 

 from such a dry extract than by the ordinary mode, but 

 there was a little difficulty in making a standardized dry 

 extract of definite strength. Experiments would have to 

 be made on that point, but he had been anxiuus to bring 

 forward his present preparation before the meetings of the 

 session terminated, in order that it miyht be criticized 

 and tested by good pharmacists. He had put himself in 

 communication with such men as merchants who were deal- 

 ing with these barks, and the opinion which they had 

 uniformly expressed was that succirubra bark would be 

 the bark of the future, as far as application in pharmacy 

 was concerned. It was not the object of his paper to 

 indicate what ought to be the characters of the succi- 

 rubra bark which was selected for use. That was a per- 

 fectly distinct question, in which he should look to his 

 colleague (Professor Bentley) to take a leading part. Mr. 

 Howard had told him that there was an abundance of 

 succirubra bark which contained more than 10 per cent 

 of the mixed alkaloids. In his paper he had put out of 

 account the low class barks ; but, taking the Indian succi- 

 rubra bark, he maintained that the process which he 

 had given was a process which was applicable to any such 

 bark, and that by means of it they could get a valuable 

 and suitable preparation for use in medicine. He had not 

 yet been able to get samples of all the various qualities 

 of succirubra bark. He was desirous of taking a low class, 

 a medium, and a high class, and ascertaining whether there 

 was any fixed relationship between the alkaloidal strength 

 and the amount of extractive matter, or what he might 

 call the extractive strength, of the different qualities. 

 He wished to ascertain whether the cinchotannic acid, and 

 the fine aroma and flavour which he regarded as one of 

 the most valuable medicinal constituents of the bark, bore 

 any fixed relationship to the alkaloids which were present, 

 in the same way that, according to Mr. Dunstan's showiug, 

 the extractive matter of nux vomica bore a uniform re- 

 lationship to the alkaloids contained in the drug. This 

 was one of the points which would have to be determined 

 before an extract of this description could be standardized. 

 Mr. Giles had thrown out a doubt whether the small 

 quantity of hydrochloric acid which was used was suffici- 

 ent to exhaust the bark. He could vouch for the fact 

 that the liquid which came off at the end of the percol- 

 ation gave not a trace of precipitate of any kind 

 upon the addition of an excess of caustic soda, but re- 

 mained perfectly clear. He therefore contended that the 

 whole of the alkaloids were taken out. He might further 

 state that after having exhausted the bark and evaporat- 

 ed the percolate down to a low extent he got a precipit- 

 ate upon adding water. Mr. Giles had said that he need 

 not get a precipitate. He should like Mr. Giles to explain 

 how it cuuld be avoided. Some barks gave a precipitate 

 like thick mud, while other qualities gave very little ; but, 

 whatever bark was used, he held that dilution with water 

 and the throwing down of such precipitate as might be 

 formed were desirable, and that this method gave a result 

 which was in every way superior to that which was ob- 

 tained when the precipitate was left in the preparation. 

 The President said that the Professor had been wonder- 

 fully strong in reply, as he always was. It was almost a 

 greater treat to hear him reply to than to hear him read 

 a paper, for the reply contained a fire which the paper 

 often lacked. He must confess that his reply was strong, 

 except in one respect. When he told them, with the 

 dignity of a Professor, that because he found no alkaloid 

 in the percolate, the bark was exhausted, he must forgive 

 him (the President) for saying that the statement was 

 extremely weak. An analysis of the bark ought to be 



