DRYING AND PRESERVATION 



Sometimes drugs are ' worked ' before they are sold 



17 



they are then 



usually emptied on to the floor of the warehouse, mixed or sorted as 

 required, and repacked in the cases. Spices such as pepper, cloves, 

 ginger, nutmeg, cassia, pimento, and chillies, together with tapioca 

 and arrowroot, are included in the spice sales. Cinnamon auctions 

 are held once a month. 



After arrival in the drug merchants' warehouse the drugs have 

 to undergo further treatment before they are sold to the pharmacist. 



FIG. 13. Working tragacanth. (Heap.) 



They are examined, freed from dust and dirt by sifting, and graded 

 either by sifting or hand-picking ; they have frequently to be further 

 tested by assay. Few drugs, therefore, reach the pharmacist in the 

 condition in which they are imported. 



Drying and Preservation of Drugs. The various parts of plants 

 intended for medicinal use contain, when freshly collected, a large 

 proportion of water from which they must be freed unless they are 

 destined to be used in the fresh state. The following table, 1 which 

 gives the approximate amounts of air-dry drug yielded by 100 parts 

 of the fresh plant, will suffice to indicate the limits within which the 

 percentage of moisture usually varies : 



1 Tschirch, Handbuch d. Pharmakognosie. 



