RADIX IPECACUANHA. IPECAC. I07 



and, moreover, stemmy ipecac or ipecac stems are made 

 up of thick central cylinders and thin cortex. 



With greater magnification the periderm is seen to 

 consist of from four to six rows of regularly arranged cork 

 cells. Beneath this is the cortex, consisting externally of 

 isodiametric polygonal, many-angled parenchymatic cells 

 usually filled with starch, and strongly pitted with simple 

 pores. Here and there throughout the cortex are crystal 

 sacs with larger and smaller bundles of acicular calcium 

 oxalate crystals. The parenchymatic cells of the cortex 

 become more irregular and smaller as the cambium is 

 approached. The fibro- vascular bundles consist of a 

 well-developed xylem and a feebly developed phloem, 

 between which there is the delicate two- or three-layered 

 cambiimi. The phloem consists almost exclusively of 

 sieve tubes, many of which soon undergo occlusion. 

 These run out into the cortex in thin, irregular, triangular 

 wedges which vary markedly for each bundle. The xylem 

 consists of elements which are difficult of exact definition. 

 They are best termed tracheids, though many transitional 

 forms are found. True vessels in the ordinary sense are 

 missing, and when found in a powder indicate a certain 

 admixture of stem. These tracheids are radially dis- 

 posed, and are separated by bands of woody parenchyma, 

 though distinct medullary rays are wanting (separating 

 this from Gillenia, which also possesses vessels). The 

 individual cells are considered in the powder. 



Powder. — The powder (No. 60) is light grayish-brown 

 in color, and has the characteristic penetrating and 

 irritant taste and odor of the drug. 



Microscopically, the following elements enter more or 

 less conspicuously into the powder: Starch, crystals, cork, 

 parenchyma, wood fibres, tracheids and vessels. 



The starch is the most characteristic feature of the 

 powder, and is almost of diagnostic value alone. The 

 grains are simple, and in twos, threes and occasionally in 



