GENERAL PRINCIPLES AND RULES XXV 



the time of collection in different countries, as well as to its being 

 collected from different species. 



Another factor affecting the quality of vegetable drugs is 

 carelessness in drying them and caring for them after they are 

 gathered. At one time the Pharmacopoeia specified that some 

 drugs should be kept a certain length of time before being used, as 

 in frangula and cascara sagrada. In these instances the results of the 

 changes on keeping have been ascertained, and since a similar effect 

 may be obtained by heating the bark at 100 C. for forty-eight hours, 

 this specification is deemed no longer necessary. 



FIG. 2. A section of crude drug warehouse of Sharp & Dohme, Baltimore, Md. 



In some drugs a sort of ripening process takes place in the drying, 

 as in gentian, guarana, vanilla and the solanaceous leaf drugs. In 

 still others a marked deterioration takes place if they are placed in 

 heaps and allowed to ferment, as in the case of lavender and most 

 other drugs yielding essential oils. In the preparation of oil of 

 peppermint, the yield of oil is greater and the quality better if the 

 plants are allowed to dry and are distilled immediately of soon after. 

 On the other hand, the yield of methyl salicylate is greater in the leaves 

 of Gaultheria procumbens or the bark of Betula lenta if they are first 

 macerated in water for about twelve hours. 



Quite a number of drugs are not infrequently observed in com- 

 merce in a moldy condition, as taraxacum, veratrum, aconitum, zing- 



