98 The Philippine Journal of Science 1923 



the methods mentioned below, thirteen of these (£-eucaine, 

 brucine, cinchonidine, cinchonine, cocaine, coniine, heroine, hy- 

 drastine, quinoline, sparteine, strychnine, stovaine, and vera- 

 trine) give characteristic crystalline precipitates. Bolland 6 

 states that apoatropine and hydrocotarnine give crystalline plates 

 with potassium f errocyanide. Grutterink 7 includes tropococaine 

 and cotarnine. Unfortunately these four alkaloids were un- 

 obtainable by me. The crystalline compounds obtained are of 

 the addition type, and probably have the general formula 8 

 B 2 .H 4 Fe(CN) .X H 2 0. 



The sensitivity and the best method of applying the tests have 

 also been determined. 



TECHNIC 



The alkaloid or alkaloidal salt to be tested is dissolved in 

 distilled water acidified with dilute hydrochloric acid. A drop 

 of this solution is placed upon a miscroscope slide. The drop 

 should not be more than 2 to 3 millimeters in diameter. Close 

 to this drop is placed a smaller drop of a 5 per cent aqueous 

 solution of potassium ferrocyanide. By means of a platinum 

 wire or drawn-out glass rod, a tiny channel is made to flow 

 from the reagent into the test drop. Usually an amorphous 

 precipitate results which gradually becomes crystalline. If no 

 precipitate appears, or if the precipitate remains amorphous 

 after a minute or two, the preparation is vigorously scratched 

 with a platinum or glass rod. In fact, I have found that, gen- 

 erally speaking, much more characteristic and perfect crystals 

 result upon scratching and upon the use of comparatively dilute 

 alkaloidal solutions. The drop is examined under a low power. 

 The color, shape, crystal angles, polarization, extinction angles, 

 and habit aid in the identification of the crystals under exam- 

 ination. 



The sensitivity was obtained by testing solutions of the al- 

 kaloid in decreasing concentration until one was. reached that 

 failed to give crystals with the reagent within five minutes. 

 The most-dilute solution, one drop of which yields crystals within 

 five minutes, gives the sensitivity. The dilution of the drop by 

 the reagent solution must of course be taken into consideration. 



6 Bolland, A., Monatsh. 32 (1910) 120, 129. 



7 Grutterink, A., Zeitschr. Anal. Chem. 51 (1912) 175. 

 "Cuming, W. M., Joum. Chem. Soc. 121 (1922) 1287. 



