IHE ALUMNI JOURNAL. 



107 



and excess of ammonium chloride, col- 

 lecting the precipitated morphine, which 

 is dried and weighed. The assay pro- 

 cesses for opium being elaborate and 

 troublesome, it was very natural that 

 attempts should be made to devise a 

 volumetric method. Morphine is readily 

 oxidized by iodic acid, ferric salts, per- 

 manganate, and bichromate. Mylius 

 suggested the use of iodic acid, relying 

 on the amount of iodine liberated as 

 equivalent to a fixed proportion of mor- 

 phine. I have tried the addition of ex- 

 cess of bichromate of potash in acid solu- 

 tion and titration with standard ferrous 

 sulphate. But there is uncertainty in 

 all these methods. In the first place, 

 we do not know how much of the oxida- 

 tion may be due to impurities; and sec- 

 ondly, there is no evidence that a further 

 or secondary oxidation does not occur. 

 Iodine is so apt to react with alkaloids 

 that its liberation from iodic acid by 

 morphine does not appear as a promising 

 plan for the estimation of opium. Even 

 when working with pure morphine, I 

 have not obtained very constant or satis- 

 factory results, but I have only tried a 

 few experiments. The subject has not 

 been by any means thoroughly worked 

 up; it is sufficient to say that these indi- 

 rect methods are not at present of any 

 practical importance. What the analyst 

 now wants, is to get hold of the actual 

 morphine in as pure a state as practica- 

 ble and weigh it. The method of Tesche- 

 macher and Smith ("Chem. News, Iviii) 

 is one of the best for that purpose, and is 

 much relied on. The official U. S. pro- 

 cess is substantially the same, and in its 

 present form is mainly due to Dr.Squibb. 

 It consists in exhausting the opium with 

 water, concentrating, adding alcohol, 

 ether, and excess of ammonia; collecting 

 the precipitated morphine, washing with 

 alcohol and with water (both being satu- 

 rated with morphine), drying, washing 

 with benzene, drying, and weighing. A 



correction for impurities may be applied 

 by treating with lime-water, which dis- 

 solves the morphine and leaves most of 

 the impurities behind. 



Considering the useful work that has 

 been done in this subject by American 

 chemists, it was very appropriate that 

 among the first papers contributed to the 

 New York section of this Society were 

 two able communications on the assay of 

 opium. These were given by J. H. Wain- 

 wright (this Journal, 1895, 254), and L. 

 Kebler, (this Journal, 1895, 464), and 

 were followed by instructive discussion. 

 I propose to offer a few further comments. 

 In the first place, I would note that the 

 morphinate of lime and ammonium chlor- 

 ide process, formerly official in the United 

 States and now official in the British 

 Pharmacopoeia, was condemned by nearly 

 all the speakers, mildly by Dr Wain- 

 wright and emphatically by Dr. Coblentz. 

 The latter stated that the students at 

 college obtained such discordant results 

 by the process that it had to be abandon- 

 ed, while now by the Squibb method very 

 satisfactory numbers are obtained. Speak- 

 ing from a more limited experience, I en- 

 tirely concur in the condemnation. In the 

 first place the idea of taking half the solu- 

 tion as containing half the morphine of the 

 opium is a delusion and a snare. It is a 

 striking example of the danger of going 

 by theory instead of by experiment. If 

 a given weight of water be added to the 

 drug, the variable amount of soluble mat- 

 ters increasing the volume of the solution 

 will cause appreciable error. Similarly, 

 if the mixture be made up to a given vol- 

 ume, the varying bulk of the insoluble 

 portion will cause some error. But 

 there is some further source of error, and 

 it seems to me to be this. It is well 

 known that it is always difficult to ex- 

 tract the last portions of alkaloid from 

 plant tissues. The process is very little 

 anolagous to the washing, say of a sul- 

 phate of barium precipitate, where the 



