THE AL UMNI JOURNAL. 



T05 



are boiled with 500 c. c. of water, using 

 a reflux condenser, for six hours. The 

 decoction is filtered, and the filtrate made 

 up to 600 c. c. Heat to boiling, and add 

 4 grms. of acetate of lead. Attach to a 

 reflux condenser and boil for 10 minutes. 

 Filter, take 500 c. c. and evaporate to 

 about 50 c. c. Remove the excess of lead 

 by means of sodium phosphate, and final- 

 ly concentrate to about 40 c. c. The caf- 

 feine is then removed by shaking 4 or 5 

 times with chloroform. Four extractions 

 are absolutely necessary to ensure com- 

 plete extraction, and it is advisable to use 

 a fifth. 



This process I have lound to give ex- 

 cellent results. Paul's objection to it 

 that it does not extract all the caffeine 

 seems to be unfounded, for after examina- 

 tion of over 50 samples of tea, I have not 

 in any case found the process yield a less 

 amount than the alcohol process, whilst in 

 some cases it yielded considerably more. 

 From the numerous determinations made, 

 using both Paul's and Allen's methods, 

 I have selected 12 samples as showing the 

 variation in the two processes. The re- 

 maining samples yielded practically the 

 same result by both methods, Appended 

 the results are tabulated ; 



tained with alcohol, although 5 grms. of 

 the tea and magnesia mixture were in 

 these cases treated with 3000 c. c. of al- 

 cohol. Even in ordinary cases, where 

 complete extraction by this method is ob- 

 tainable, from 1 j4 to 2 litres of alcohol 

 has to be employed to secure extraction 

 of 5 grms of tea. This in itself makes 

 the process objectionable from its expense. 

 The residual caffeine could readily be ex- 

 tracted from the mixture by boiling with 

 water. 



The caffeine isolated by Allen's pro- 

 cess can be obtained in a state of perfect 

 purity very readily, but when using the 

 alcohol process it is a matter of consider- 

 able difficulty to remove the whole of the 

 green coloring matter. In all cases the 

 residue obtained from the chloroformic 

 solution was purified as carefully as pos- 

 sible. In the case of those obtained by 

 Allen's process the residues were snow 

 white and showed the melting point of 

 caffeine. In carrying out this latter pro- 

 cess I have found it advisable in some in- 

 stances to continue boiling it with water 

 for eight hours, though as a rule, six is 

 amply sufficient. Owing to the slow- 

 ness with which the decoction filters, I 

 prefer to boil the tea with the whole of 

 600 c. c. of water, and to add the acetate 

 to the solution before filtration. This 

 saves considerable time. 



In conclusion I would say that the re- 

 sults above given show Paul's statement 

 that water will not completely extract tea 

 leaves to be erroneous. Allen's process 

 is cheaper to work, less tedious, and 

 gives more accurate results than Paul 

 and Cownley's method. — Jour.Soc. Chem. 

 hid., Neiv York Section. 



In the case of samples 4, 6, 9, it will 

 be seen that the yield by Paul's process 

 is very low, compared with that yielded 

 by boiling with water. Complete ex- 

 traction could not in these cases be ob- 



OPIUM ASSAY. 



BY D. B. DOTT, F.R.S.E., F.T.C. 



Opium being one of the most valuable 

 of drugs, and the source of one of the 

 most important of the alkaloids, its ac- 



