CHARACTERISTICS OF VEGETABLE POWDERS 49 



characteristic moldy or musty odor. If left to itself the fungus 

 finally ceases growing, due to lack of nourishment. The white color 

 due to the presence of the living hyphae then disappears and the at- 

 tacked portions of the drug gradually assume a darker coloration. 

 Drugs thus attacked are worthless because of the decomposition of 

 most of the active constituents. Leaves and herbs are especially 

 liable to be attacked by molds; to a somewhat lesser degree, also 

 larger roots and rhizomes. Not only are crude drugs attacked by 

 these fungi, but powdered drugs as well, also extracts, tinctures and 

 more especially the syrups. The spores of the molds are to be found 

 everywhere, and are carried about by air currents; hence it would be 

 impossible to exclude or destroy the spores. It is, therefore, necessary 

 to prevent their germination, and, very fortunately, this can be done 

 quite readily in the case of vegetable drugs, whether crude or powdered. 

 The greatest foes to the development of fungi, molds and bacteria in 

 particular, are dryness, cold and sunlight. Therefore, carefully drying 

 all vegeteble drugs and storing them in dry containers in a dry, cool 

 and well- ventilated store-room, will prevent the development of fungi, 

 even though the spores may be present. It is, however, not advisable 

 to keep drugs exposed to sunlight, as that hastens the destructive 

 changes of the active constituents. 



Microscopically, the presence of a fungus, whether spot fungus or 

 mold, is readily detected by the presence of the characteristic hyphse, 

 which are not readily mistaken for anything else. 



c. Lichens. 



Lichens are a very interesting group of plants, resulting from the 

 symbiotic association of a fungus and an alga. They, therefore, pre- 

 sent the histological characteristics of certain hyphal fungi and some 

 of the lower usually single-celled algae. 



These plants never develop upon the drug itself. When present 

 it may be known that they developed upon the drug-yielding plant 

 before the drug was collected. They are found upon the exterior 

 surface of some unpeeled tree barks. Lichens never develop under 

 ground, hence they are not found upon root barks or other subter- 

 ranean plant organs. Their presence is, therefore, diagnostic of stem 

 barks, though it must not be supposed that they are found on all 

 stem barks. They appear most commonly as circumscribed patches, 

 varying in size and color (crustose lichens). The predominating colors 

 being ash gray, with perhaps a greenish tinge, some are reddish yellow 

 or orange. The apothecia may resemble those of spot fungi or they 

 may be linear (Gr aphis). Sometimes remnants of foliose lichens 



