2 DEFINITIONS 



which is shown by their names and chemical formulse, are obtained 

 from the inorganic. The greater number, probably, are derived from 

 the vegetable kingdom or from plants. All the different parts of a 

 plant may be used in medicine but the active principle to which the 

 action of each is due is usually found more abundantly in certain 

 parts than others. In such cases the part or parts containing the 

 largest amounts are used. The active principle may, however, be 

 quite evenly diffused throughout, in which case the entire plant may 

 be used. 



GROSS ANATOMY OF PLANTS 



Underground Portions. These include the root, rhizome, tuber, 

 bulb and corm. The root is that portion usually without chlorophyll 

 which does not have power to produce leaves. Eoots sometimes 

 possess a bark which is used separately (Sassafras). Ehizomes are 

 the underground portions capable of producing leaves (Hydrastis). 

 A tuber is a portion of the root greatly thickened which serves for the 

 accumulation of reserve food materials (Aconite). A bulb is an 

 increase in size of the root leaves (Onion, squill), while a corm is 

 the thickened lowest part of the stem (Colchicum). 



Portions above Ground. If the entire plant above ground is 

 used, it is termed herb (Herba, Species) and consists of the leaves, 

 stems, and sometimes of the flowers and fruit. 



Stem. In herby plants it is termed stipes, in larger plants it is 

 transformed into wood (Lignum) and covered with a bark (cortex). 

 The leaves (folia) consist of a leaf stem (petiolus) and blade 

 (lamina). There are also the flowers (flores), and fruit (fructus) 

 or seed (semenis). Besides the above, certain drugs consist of the 

 juices of plants and are without definite structure (Opium, aloes). 



CHEMISTRY OF PLANTS 



The chief elements found in plants are Carbon, Hydrogen, Oxy- 

 gen and Mtrogen. These elements usually occur in combinations as 

 fats, carbohydrates, tannins, resins, alkaloids, glucosides, acids, ter- 

 penes, etc., together with inorganic salts. 



ALKALOIDS 



Many of the most important and active plant constituents are 

 alkaloids. They may exist in almost any part of the plant but are 

 frequently found in the largest proportions in the seed and roots. 

 They represent, in the greater number of cases, the active principle 

 of the plant from which they are obtained and many of them are 

 classed with the most powerful poisons. 



Definition. Alkaloids may be defined as natural-nitrogenous 

 Organic bases, i.e., they are organic substances containing nitrogen, 



