of molasses was secured from a house where no sulphur is used. In one experiment the distillate was collected in bromin water after washing with cadmiumchlorid solution, and the sulphur determined gravimetrically in the cadmium sulphid as well as in the filtrate from it combined with the bromin water. In a second determination the official method was used, the dilution in the distilling flask and the quantity of liquid distilled over being the same as in the first experiment. It was found that the official method yielded considerably more "sulphur" than was obtained by the gravimetric determination. However, this discrepancy is partly due to the fact that in spite of the U tube provided for in the official method some iodin volatilizes during the distillation. This could easily be shown by connecting the U tube with a glass tube extending into a small flask which contained a solution of potassium iodid. When the distillation was finished the potassium iodid had taken up a considerable quantity of iodin, not enough, however, to make up for the difference from the gravimetric method.

Several experiments conducted with and without the use of a current of carbon dioxid proved the necessity of using this precautionary measure, although the influence was not so great as we had anticipated. The inlet tube for the carbonic acid gas must extend into the liquid to prevent it from distilling back into this same tube.

After these preliminary experiments the following mode of procedure was adopted, avoiding the errors recognized so far: Transfer 50 grams of molasses to a flask of sufficient capacity and make up to 400 cc with air-free water. Close the flask with a rubber stopper (rubber can safely be used at this point) having three perforations. One of these is for the inlet tube for the carbon dioxid, the second for a small separatory funnel filled with glacial phosphoric acid, the third for a catch-all connected by means of a good cork with a Liebig condenser. Connect the other end of the condenser with a glass tube leading into a filtering flask containing a small quantity of a 2 per cent solution of cadmium chlorid. The glass tube must terminate below the surface of the liquid. After the filtering flask follows a Ū tube containing a little water and then a glass tube leading into bromin water in a little Erlenmeyer flask. The U tube prevents sucking back of the bromin water into the cadmium solution. After the receivers have been put in place, carbon dioxid is passed through the entire apparatus for about ten minutes. Then about 5 cc of phosphoric acid are added from the separatory funnel and 200 cc of the liquid distilled over. When the distillation is finished, the bromin water in the Erlenmeyer and the contents of the U tube are transferred to a beaker, and the cadmium solution containing the distillate is filtered into the bromin water. The excess of bromin is boiled off and the sulphuric acid is precipitated as barium sulphate and weighed. If the hydrogen sulphid is to be determined also, the cadmium sulphid is dissolved in bromin water and the solution treated like the others. It was deemed inadvisable to distil to a smaller volume than 200 cc in order to avoid charring of the mass at certain points and subsequent reduction of sulphuric acid.

Finally the influence of concentration was studied and very surprising results obtained. When the same quantity of molasses was diluted in one case to 600 cc and in the other to 400 cc, both being distilled down to 200 cc, the first experiment gave a much higher result than the second. This experience led us to investigate how much of the liquid must be distilled to obtain the entire quantity of SO2. It was found that by adding again 200 cc of water after having distilled from 400 to 200 cc new quantities of sulphurous acid were obtained, and it was necessary to repeat this procedure four times to distil

over practically all of the SO2. In this case the last distillate contained only traces of sulphur. It was thus shown that by distilling over 800 cc the SO2 could be satisfactorily determined. The method would be facilitated by making up 50 grams of molasses to 1,000 cc and distilling down to 200 cc. In this case the receivers had naturally to be changed to some extent. Results agreed practically with those obtained by separate distillations. After the true amount of SO2 in a certain molasses had been determined in this way, the official method was tested for its accuracy. By distilling in the same way from 1,000 cc to 200 cc of a N/10 iodin solution for the collection of the distillate and titrating with thiosulphate, results considerably higher than those by the above method were obtained.

The necessity of distilling off 800 cc of liquid renders the method very tedious, and it would be desirable to devise one which requires less time and labor. It is possible that the sulphurous acid may be determined in some other way than distillation. Direct titration is impossible on account of the dark color of the products under examination, but some method of precipitation may directly or indirectly accomplish the purpose. It would also be desirable to find some method by which the different forms of sulphur dioxid in molasses could be distinguished.

Mr. Wiley called attention to the value and timeliness of Mr. Zerban's paper, inasmuch as both State and Federal food officials are concerned with the difficulties in distinguishing between natural sulphur and added sulphites.

Upon motion by Mr. Wiley, election of officers was made special order for 10 o'clock Friday; and on motion by Mr. Van Slyke reports of all special committees, except the committees on recommendations of referees, were made special order for 11 o'clock.

The association adjourned for the day.

THIRD DAY.

FRIDAY-MORNING SESSION.

REPORT ON MEDICINAL PLANTS AND DRUGS.

By L. F. KEBLER, Referee.

The burden of other work imposed upon the staff of the drug laboratory and other pharmaceutical chemists of the country in consequence of recent food and drug legislation, both National and State, has interfered somewhat with the prosecution of the cooperative work on drug assaying during the past year. It is hoped that when the most urgent problems have been solved the study of methods will receive an amount of attention commensurate with its fundamental importance. In the meantime it has been deemed advisable not to depend upon the cooperation of chemists generally in the work, but to continue the same within the drug laboratory as circumstances permit until the time is more propitious for general participation.

In view of the legal status conferred upon the United States Pharmacopoeia, Eighth Revision, it seemed desirable to study all of the plant drug assays official therein, comparing them with some of the best available nonofficial methods. After this work was begun, the committee of revision of the Pharmacopoeia promulgated two lists of additions and corrections under date of May 1 and June 1, 1907, which introduced some minor changes in the details of certain methods. These changes were recognized in the work subsequently done.

The work this year covered methods for the assay of aconite leaves, aconite root, belladonna leaves, belladonna root, cinchona bark (yellow and red), coca leaves, colchicum corm and colchicum seeds. Samples of these drugs, delivered as being of United States Pharmacopoeia quality, were made the basis of study, and the following programme of work was pursued by three collaborators in the drug laboratory. All calculations and solutions, except as otherwise specified, were based on the data of the United States Pharmacopoeia, Eighth Revision.

DIRECTIONS FOR THE WORK.

VOLUMETRIC SOLUTIONS.

Prepare a standard normal sulphuric acid, determining the factor by two or more of the following methods:

(1) The United States Pharmacopoeia method by titration with normal potassium hydroxid solution which has been standardized against purified potassium bitartrate.

(2) By titration of the ignition residue from a weighed portion of potassium bitartrate.

(3) By titration of a weighed amount of freshly ignited sodium carbonate. (4) By precipitation as barium sulphate and gravimetric determination. (5) By evaporation with slight excess of ammonium hydroxid, and determination after drying at 125° C. as ammonium sulphate.

From this normal acid prepare a decinormal sulphuric acid by dilution. Prepare a fiftieth normal solution of potassium hydroxid and determine the factor by titration with the decinormal sulphuric acid prepared as just directed.

DETERMINATION OF ALKALOID.

Total extraction method.

Into a 200 cc flask weigh 10 grams of the powdered drug, add about 75 ce of ether-chloroform mixture (5 to 1 by volume), rotate and add 5 ce of a mixture

of 40 cc of strong ammonia water with 60 cc of alcohol, cork, shake well and often during one hour, and let stand over night. Transfer as much of the mixture as possible to a small percolator, the neck of which is provided with a purified cotton plug, receiving the percolate in a beaker or flask. Rinse the residue in the flask into the percolator with additional portions of the etherchloroform mixture, packing it down moderately with a glass rod, and continue the percolation with the same mixture until the percolate does not give an alkaloidal reaction, or at most only an opalescence when 2 cc are evaporated, and the residue is treated with N/10 hydrochloric acid, the mixture filtered and the filtrate tested with Mayer's solution. Evaporate or distil the percolate to about 10 cc at a temperature not exceeding 70° C. Transfer to a separator, and rinse the vessel with two portions of 20 cc each of ether, alternating with two portions of 10 cc each of 2 per cent sulphuric acid. Shake out, making sure that the reaction is acid, and repeat the operation three times with 15 cc of the same strength of acid, filtering the acid solutions into another separator through a 7 cm filter, and rinsing the latter with a few cubic centimeters of water. Wash the acid solution with 10 cc of ether-chloroform mixture (1 to 3 by volume), discarding the latter, and if colored repeat until no more color is acquired. Make the solution alkaline with ammonia water and shake out with four successive portions of about, 20 cc each of ether-chloroform mixture (1 to 3); collect the latter in a separator, wash with 5 cc of water, transfer the ether-chloroform mixture to a tared flask or beaker, rinsing the separator with a small portion of ether-chloroform, and evaporate the solvent at a temperature not exceeding 70° C.

(a) Gravimetric. Add 3 cc of ether, evaporate and dry to constant weight at a temperature not exceeding 70° C. Report weight of alkaloidal residue. (b) Volumetric. Dissolve the residue in about 10 cc of neutral alcohol, add 25 cc of water, 3 to 15 drops of cochineal indicator solution, measure in from a burette a slight excess of N/50 sulphuric acid, mix intimately, and titrate back with N/50 potassium hydroxid. Report net amount of N/50 acid required.

Aliquot method.

Into a 200 cc flask weigh 15 grams of the powdered drug, add 150 cc of etherchloroform mixture (5 to 1 by volume), cork and shake often for several minutes. Add 10 ce of ammonia water (10 per cent), shake frequently during one hour, and let stand over night. Add 15 cc of water, or sufficient to agglomerate the drug, shake, let settle a few minutes, and then decant 75 cc of the clear solution into a graduated cylinder. Transfer the solution to a separator, rinsing the cylinder with a few cubic centimeters of ether-chloroform, and shake out with 20 cc (or sufficient to render acid) of 2 per cent sulphuric acid, repeating the operation three times with 15 cc of the same strength acid, and collect the acid solutions in another separator. Wash the acid solution with 10 cc of ether-chloroform mixture (1 to 3 by volume), discarding the latter, and, if colored, repeat until no more color is acquired. Make the solution alkaline with ammonia water, and shake out with four successive portions of about 20 cc each of ether-chloroform mixture (1 to 3); collect the latter in a separator, wash with 5 cc of water, transfer the ether-chloroform mixture to a tared flask or beaker, rinsing the separator with a small portion of etherchloroform, and evaporate the solvent at a temperature not exceeding 70° C. (a) Gravimetric. Add 3 cc of ether, evaporate and dry to constant weight at a temperature not exceeding 70° C. Report weight of alkaloidal residue. (b). Volumetric. Dissolve the residue in about 10 cc of neutral alcohol, add 25 cc of water, 5 to 15 drops of cochineal indicator solution, measure in from a burette a slight excess of N/50 sulphuric acid, mix intimately, and titrate back with N/50 potassium hydroxid. Report net amount of N/50 acid required. Whenever iodeosin indicator is used, follow the directions of the United States Pharmacopoeia VIII, page 542. Solutions standardized by means of cochineal should not be used with iodeosin without running a blank for comparison, as the indicators do not give the same neutral point.

These methods and those referred to in the United States Pharmacopoeia are applied to the analysis of the following drugs with the modifications noted.

ACONITE ROOT.
Method I.

U. S. Pharmacopœia VIII, p. 28. Report the amount of N/10 acid required.

Method II.

Aliquot gravimetric. Use ether instead of ether-chloroform mixture in the final shaking out.

BELLADONNA LEAVES.

Method I.

U. S. Pharmacopoeia VIII, p. 67. Report indicator used and amount of N/10 acid required.

Aliquot volumetric.

Method II.

BELLADONNA ROOT.

Method I.

U. S. Pharmacopoeia VIII, p. 68. Report indicator used and amount of N/10 acid required.

Aliquot volumetric.

Method II.

CINCHONA BARK.

Method I.

U. S. Pharn.acopoeia VIII, p. 102. Report total and ether-soluble alkaloids.

Total extraction, gravimetric.

Method II.

COCA LEAVES.
Method I.

U. S. Pharmacopoeia VIII, p. 106. Report indicator used and amount of N/10 acid required.

Method II.

Aliquot gravimetric. Use ether instead of ether-chloroform mixture through

out.

COLCHICUM CORM.
Method I.

U. S. Pharmacopoeia VIII, p. 111. Report weight of alkaloidal residue.

Method II.

Exhaust 10 grams of the powdered drug by percolation with alcohol, add 25 ce of water to the solution and evaporate. Digest and stir the residue for several minutes with 25 cc of petroleum ether and transfer the liquid to a beaker, rinsing the residue with a little fresh petroleum ether. Add to the beaker 20 cc of water and evaporate the petroleum ether. Gently warm the first residue with 10 cc of water, cool, and filter the solution through a small filter into a separator, rinsing the vessel, and filter with several small portions of water and finally with the water in the beaker. Shake out the liquid with four portions of 10 cc each of chloroform and evaporate the latter in a tared dish. Add 3 cc of alcohol and evaporate, repeat the operation and dry the residue to constant weight at a temperature not exceeding 70° C. Report weight of alkaloidal residue.

COLCHICUM SEED.
Method I.

U. S. Pharmacopoeia VIII, p. 112. Report weight of alkaloidal residue.

Method II.

See Colchicum Corm. Method II.

STANDARDIZATION OF VOLUMETRIC SOLUTIONS.

In order to compare the present pharmacopoeial method for preparing volumetric solutions, a quantity of potassium bitartrate was purified according to the prescribed directions of the Pharmacopoeia. Two equal parts of this purified potassium bitartrate were weighed out, one portion ignited at a low red temper