7 * 
German Pharmacopoeia® recommends haematoxjdin as indicator in 
the titration of quinine, while according to Hille^ there is an error 
when quinine is titrated with hsematoxylin as indicator which is in 
many cases equivalent to a whole cubic centimeter of N/10 alkali. 
Likewise, Messner^" has tested the various indicators recommended 
for the purpose of titrating the cinchona alkaloids and found most 
of them, with the exception of lacmoid, to be unsuitable. Similarly, 
the adoption of hsematoxylin as indicator in certain of the alkaloid al 
assays given in the U. S. Pharmacopoeia (1905) is condemned by 
Lyons‘S and also by Francis,^ who prefer cochineal as the indicator. 
Finally, we may perhaps best illustrate the imperfect condition of 
the acidimetric processes for estimating alkaloids by the use of 
various indicators, each more or less suitable to particular alkaloids, 
by the circumstance that the revisers of the U. S. Pharmacopoeia 
(1905), at present official, apparently deemed it better to include no 
quantitative method whatever for the determination of the actual 
amount of alkaloid in specimens of such an important alkaloid as 
quinine,-^ for example, rather than adopt an acidimetric estimation by 
means of any of the several indicators proposed. And the reason 
for such course is also readily seen; for having apparently selected 
iodeosin and haematoxylin as the most suitable indicators in the alka- 
loidal titrations, the former could not be used in the case of quinine, 
since it is entirely unsuitable as an indicator in quinine titrations, 
as shown by Kippenberger, ^ while hsematoxylin, although better 
suitable than iodeosin, is still incapable of yielding satisfactory 
results, as pointed out by Hille.^ 
Another method for the estimation of alkaloids, in which the indi- 
cator employed is phenolphthalein, is the method proposed by 
Gordin.^ This author found that the periodides or mercuriodides of 
alkaloids, precipitated by Wagner’s and by Mayer’s reagent respec- 
tively, always carry down with them an amount of hydriodic acid 
which appeared to be proportional to the amount of alkaloid in the 
solution. Gordin therefore sought to apply this property of alka- 
loids to their volumetric estimation with the aid of phenolphthalein 
as indicator. His method as applied to morphine, for example, is 
as follows: About 0.2 gm. of the sample of morphine to be examined 
is dissolved in 30 cc. of standard hydrochloric acid (about N/20) in a 
100 cc. flask, Wagner’s reagent (containing about 1 per cent of free 
aApoth. Zeit., 22, 1117 (1907). 
& Arch. Pharm., 241, p. 106 (1903). 
<^Zeit. angew. Chem., 16 , 444-450 and 468-477 (1903). 
d Proc. A. Ph. A., 54, 441 (1906). 
eProc. A. Ph. A., 54, 454 (1906). 
/U. S. Pharmacopoeia (1905), pp. 373-4. 
^ Zeit. anal. Chem., 39 , 205 (1900). 
h Loc. cit. 
