CHARACTERISTICS OF VEGETABLE POWDERS 47 



close microscopical examination of the outer layers of barks, the epi- 

 dermis of flowers, leaves, roots and rhizomes, will reveal the presence 

 of bacteria, insect remnants, low forms of algae, besides other foreign 

 substances which are carried to the plants by air and water currents, 

 and are, therefore, normally and unavoidably present and are not an 

 indication of a poor quality or an adulteration of the drug. 



a. Bacteria. 



Bacteria are practically omnipresent. Owing to their minuteness 

 they are transported from place to place by the slightest air currents. 

 They are circulated in the soil by the currents caused by rains and the 

 evaporation of moisture. They cling to all exposed plant parts. In 

 spite of their omnipresence they probably do not develop in or upon 

 dry drugs in sufficient numbers to produce any material change. 



Bacteria are normally present in large numbers in some vegetable 

 substances, as the seeds of Abrus precatorius, the leaves of Drosera 

 and Nepenthus and the root tubercles of leguminous plants. They 

 are abnormally present in many drugs. For instance, gum opium is 

 mixed with bacteria of the air, dust and dirt and from the often dirty 

 hands and instruments of the collectors. Manna, aloes, gums, solid 

 extracts and gelatine, are among the substances which usually contain 

 bacteria in large numbers. Some of the very important fermenta- 

 tive changes which take place in drugs during the various stages of cur- 

 ing are, in all probability, induced by bacteria. German investigators 

 have shown that the flavor of tobacco is dependent upon the species of 

 bacterium which causes the fermentative changes during the " sweat- 

 ing process." Future investigations may go to prove that the variable 

 deterioration of stored drugs is due to the presence of bacteria which 

 decompose the alkaloids and other active constituents. 



Bacteria and higher fungi frequently cause disease, death and decay 

 of plants and fresh vegetable substances, as, for instance, pear blight, 

 apple blight, carnation blight, rotting of fleshy fruits, of tubers, bulbs 

 and fleshy roots; but since only few drugs are used in the fresh state, 

 these destructive organisms concern the pharmacist but little. One 

 of the highly important pharmaceutical researches will be along the 

 line of microbial decomposition changes in Pharmaceuticals of all 

 kinds and of soda fountain syrups and extracts. Thus far no one has 

 seriously considered these vital problems. 



b. Hyphal Fungi. 



Hyphal fungi are higher in the scale of evolution than bacteria, 

 and are designated hyphal because they consist of a more or less 

 densely interwoven network of usually branching elongated (filamen- 



