268 



HOLMES. 



The following quantitative determinations were made with a solution 

 of pure codeine in water. In each experiment the solution was made 

 up to a volume of 200 cubic centimeters. 



Table IX. — Action of Wagner's reagent with aqueous solutions of codeine. 



Number 

 of exper- 

 iment. 



Grams 

 alkaloid. 



N 



jq iodine- 



Atoms of iodine per 

 molecule of code- 

 ine in— 



Added. 



Used up. 



Solution. 



Perio- 

 dide. 



73 



74 

 75 

 76 

 77 

 78 

 79 

 80 

 81 

 82 

 83 

 84 

 85 



0.03823 

 0. 03823 

 0.03823 

 0. 03823 

 0. 03823 

 0. 03823 

 0. 03823 

 0. 03823 

 0. 03823 

 0. 03823 

 0. 03823 

 0. 03823 

 0. 03823 



cc. 



2.01 



2.01 



2.01 



5.14 



10.05 



10.09 



15.35 



15.27 



20.33 



30.48 



50.25 



100.50 



145. 22 



cc. 

 0.17 

 1.49 

 1.39 

 2.70 

 5.69 

 5.93 

 8.07 

 8.07 

 8.72 

 9.38 

 10.69 

 15.90 

 18.46 



1.56 

 1.56 

 1.56 

 4.02 

 7.86 

 7.89 

 12.04 

 11.94 

 15.89 

 23.83 

 39.32 

 78,64 

 113.62 



0.14 

 1.16 

 1.08 

 2.12 

 2.46 

 2.64 

 6.32 

 6.32 

 6.82 

 7.34 

 8.36 

 12.44 

 14.44 



It will be seen that the amount of iodine which combines with the 

 alkaloid is dependent in a more or less regular degree on the concen- 

 tration of iodine in the solution. In experiments numbered 73, 74, and 

 75, of which number 73 was made with 0.25 gram of sulphuric acid and is 

 included in the table merely for purposes of comparison, no precipitates 

 were formed. In the others, precipitates were obtained which, in a 

 general way, resembled those from acid solutions. However, these com- 

 pounds were not crystalline, and the accuracy of the work was somewhat 

 impaired because it was impossible to secure absolutely clear filtrates in 

 the determinations with the higher concentrations of iodine. 



HEROIN. 



A similar series of determinations was made with a solution of pure 

 heroin in distilled water. The solubility of this alkaloid at room 

 temperature (about 30°) was found to be approximately one part in 

 twelve hundred of water. In the present work, the concentration of 

 heroin was only one part in twenty-five thousand, yet very decided 

 precipitates were obtained and a test with one part in two hundred and 

 fifty thousand gave a perceptible cloudiness, observable through a con- 

 siderable layer of solution. Wagner's reagent, therefore, gives an ex- 

 tremely delicate qualitative test for heroin in the absence of acids. 



