302 SUBTERRANEAN ORGANS 



Varieties and Substitutes. Genuine Pareira brava appears at 

 uncertain intervals on the London market. Its place has for some 

 years been frequently taken by the root of a Menispermaceous plant 

 of unknown botanical origin. This, the common substitute, may be 

 distinguished by its distinctly brownish colour, the larger number of 

 narrower zones which are not distinctly crenate, the larger 

 vessels in the wood, and the less bitter taste. The drug is, further, 

 not so heavy as true Pareira brava, and does not exhibit, when cut 

 transversely, the same waxy nature. In addition to the above 

 differences this false Pareira contains scarcely any fat, yields less 

 ash (about 1-3 per cent.), and less aqueous extract (about 6 per cent.). 



Occasionally the stems of the plant are mixed with true Pareira 

 brava ; these are paler in colour, frequently bear the minute apothecia 

 of lichens, and exhibit a small pith. 



Other substitutes have occurred, and are likely to occur ; it is 

 essential therefore, in this as in all cases, that the student should 

 make himself familiar with the characters of the true drug, so as to 

 be able to distinguish it from any substitute that may occur at any 

 time. 



CALUMBA ROOT 



(Colombo Root, Radix Calumbae) 



Source, &C. Calumba root is obtained from Jateorhlza Coluniba y 

 Miers (N.O. Menispermacece), a lofty climbing plant with annual 

 herbaceous stems and swoUen fleshy roots. It is indigenous to 

 Portuguese East Africa, growing in abundance in the forests in the 

 region of the Zambesi. The root is much used by the natives as a 

 remedy for dysentery and other diseases, and also on account of the 

 yellow colouring matter it contains. It was brought to Europe 

 towards the end of the seventeenth century, and after being long 

 neglected came at last into general use. The roots are dug in the 

 dry season, cut into transverse slices, and dried. The drug as imported 

 is of a dingy brown colour and has a quantity of brown powder (soil) 

 adhering to it (' natural ' calumba root). It is cleaned by washing 

 and brushing, and is then graded for sale (' washed ' calumba root). 

 The following description applies to the washed root, which is the 

 official variety. 



Description. Calumba root occurs in commerce in irregular, 

 elliptical or nearly circular slices averaging about 4 cm. in diameter 

 and 6 mm. in thickness, but often much larger and thicker. They 

 are usually depressed in the centre on both sides, the tissue there 

 being apparently less loaded with starch and less woody than the outer 

 portions, and consequently contracting more on drying. The exterior 

 of the root is covered with a thin, dark, brownish, wrinkled cork, 



