38 TECHNICAL DRUG STUDIES. 



similar reactions were obtained with any of the other drugs men- 

 tioned. 



These facts are, as previously stated, especially important when 

 only small quantities of material are available, and further complica- 

 tions arise when mixtures are under examination. The similarity 

 of the colors given by the coca and belladonna alkaloids is of special 

 interest inasmuch as they are often found together. However, if 

 cocain is present it will be at once apparent by the characteristic 

 odor of ethyl benzoate, which is given off on the addition of the alco- 

 holic potash, and, furthermore, the physiological effect on the tongue, 

 together with the microscopic examination of its well-known salts, 

 will substantiate its identity. The mydriatic effect of atropin can 

 not be relied upon as an absolute proof of its presence in a mixture of 

 this kind, because cocain has mydriatic properties, but atropin is 

 much less soluble in petroleum ether than is cocain, and while two or 

 three shakings with the solvent will usually remove the cocain and 

 leave nothing in the coca extract giving Vitali's test to go into the 

 chloroform solution, most of the atropin will be left in solution and 

 when removed by the chloroform may be identified by this reaction, 

 by its characteristic microscopic salts, and by other tests. It should 

 be remarked that the purple color was obtained only when working 

 with coca extract. The alkaloids cocain and tropacocain purchased 

 on the market did not respond to this reaction, and in fact a very pure 

 petroleum ether residue was found to give but a slight purple color. 



In the case of nux vomica and belladonna the difference in the 

 physiological properties of the alkaloids taken in conjunction with 

 their characteristic microscopic salts would be sufficient to remove 

 any doubt as to whether one or both of these drugs were present. In 

 this connection it is of interest to note that pure strychnin was 

 found to give the Vitali reaction the same as the extract from nux 

 vomica. 



If a mixture of coca, belladonna, and nux vomica is suspected, the 

 identification of the atropin presents greater difficulties; or if one 

 finds both cocain and strychnin in a product, it is not always an easy 

 matter to state absolutely whether atropin is or is not present. 

 Careful examination of the microscopic appearance of the precipi- 

 tates given with the different alkaloidal reagents is necessary, together 

 with further substantiation by the physiological action of the chloro- 

 form residue on the pupil of the eye, after it has been fully estab- 

 lished that the cocain has previously been removed by petroleum 

 ether. 



When experimenting with a mixture of this description the atropin 

 may be separated by obtaining a concentrated solution of the alka- 

 loids in dilute sulphuric acid and precipitating the strychnin and 

 cocain by platinic chlorid. Atropin is not thrown down, and by 



