53 



are not characteristic. Fig. 47 vshows the elements of aid in the 

 diagnosis of this drug. 



Fig. 47. Nux Vomica. 



Figure 47 

 (1) Epidermal cells and (2) Oil cells. 



OAK BARK. 



(Quercus alba.) 



White oak bark is occasionally used as a drug and occurs as 

 a light brown powder, of no particular odor, but having a some- 

 what characteristic astringent taste. One or two elements of the 

 powder are useful in its diagnosis. Long, thick walled lignified 

 bast fibres are found, and also crystal cells containing rosettes 

 or monoclinic prisms of calcium oxalate about 10 — 20/x.in diameter. 

 There are also found thick walled stone cells with numerous la- 

 mellae and simple pores. The parenchyma, while not character- 

 istic, contains irregularly shaped brownish tannin masses. The 

 characters noted above will be found illustrated in Fig. 48. 



Fig. 48. 



Figure 48 

 Oak Bark. (1) Bast fibres; (2) Crystal cells and (3) stone cells. 



SASSAFRAS. 



{Sassafras officinale.) 

 This powdered drug is light brown in color, and possesses a 

 characteristic aromatic odor, and has an astringent, aromatic, 

 somewhat mucilaginous taste. Its presence can usually be de- 

 tected by these characteristics when present in any quantity. 



