A TKST I'OU HASHISH 25 



A TkST KOlt HA8H1S1I 



A reliable chemical test for hashish has long been a desideratuni. The material, 

 when pure, is sufficiently easy of identification, by reason both of its appearance and 

 characteristic odour. In the great majority of instances, however, it is encountered in 

 admixture with such substances as cloves, pepper, cinnamon, etc. This is usually the 

 case with the native aphrodisiacs which often contain a small proportion of opium as 

 well. The detection of small quantities of hashish in these mixtures has been extremely 

 difficult and usually impossible. The fcjUowing simple method has been found to be 

 most satisfactory, and if propei- precautions be taken, quite delicate. It depends upon 

 the fact that the resinous matter of hashisli strikes a marked purple colour on treatment 

 with potash or soda. Tlie test may bo applied as follows ; the material suspected to contain Details of the 

 hashish is treated with petroleum-ether, the liquid passed through a filter and the ether '^'^' 

 evaporated to dryness in a small porcelain crucible. In the presence of any considerable 

 amount of hashish a marked amoiuit of tar-like residue is left ; l^ut if only a small 

 amount is present there may only be a light yellow stain. To this residue a few drops 

 of alcoholic potash are added, and the mixture evaporated to dryness on the water-bath. 

 In the presence of hashish a rich purple colour is gradually developed. On dilution 

 with water the colour takes on a more bluish cast. It is very permanent. 



The purple colour is due to an oxidation product. If the evaporation of the 

 petroleum-ether extract and alkali be conducted in an atmosphere free from oxygen, 

 only a brown colour results. 



Any of the ordinary resin solvents, alcohol, ether, acetone, benzene, chloroform, carbon 

 disulphide or petroleum-etlier may be applied to the extraction. Petroleum-ether is 

 perhaps the most satisfactory, but it might conceivably be of advantage in special cases 

 to employ one of the others in order to avoid the solution of material with which the 

 hashish is associated. 



The richest purple colour is obtained by extraction and evaporation in the cold. If 

 the hashish be completely exhausted by prolonged extraction with warm petroleum- 

 ether, as in a Soxhlet apparatus, the extract may not respond to the test, or only with 

 difficulty. The colour developed by an extract so obtained is reddish, being masked by 

 the brown tint due to the effect of the alkali on the associated extracted matter. 

 There appears to be evidence also that the active body in the extract is gradually 

 destroyed by such treatment. 



Extracts of this kind may be made to yield a more characteristic reaction by 

 treating the residue, spread out in a thin layer on porcelain, with strong aqueuus potash 

 or soda, but the colour may not appear for some hours. 



.1. A. Goodson, who has carried out nnieh of the investigation in coimection with 

 the test, suggests the following method of application, which may be found useful when 

 the hashish is mixed with other highly-coloured bodies. The extraction is made in 

 the usual manner, the petroleum-ether treated with alcoholic alkali and evaporated to 

 dryness. Tlie resin acids are then liberated by the addition of a few drops of dilute 

 acid, brought on to a filter and dissolved by the addition of a small amount of petroleum- 

 ether. The liquid is then underlaid in a test-tube with weak aqueous soda or potash. Variants of 



The purple colour appears at the junction of the two liquids and, if the alkali solution 'he method. 



T • 1 1 1 1 • mi ^^^ special 



IS not too strong, is distributed throughout it. The colour is developed at once, since circumstances 



the resin acids have already been exposed to the air. 



The test may also be made by the direct addition of the aqueous alkali to the 



