132 



SCIENTIFIC AND APPLIED PHARMACOGNOSY 



Powder. (Fig. 56.) Blackish-brown; calcium oxalate in mono- 

 clinic prisms 0.007 to 0.035 mm. in length, or in raphides about 0.4 

 mm. long; occasional unicellular glandular papillae with rounded 

 summit and containing oil-like globules of a balsam; sclerenchy- 

 matous fibers more or less thick-walled, strongly lignified and with 

 numerous oval pores; trachea with spiral or reticulate thickenings; 

 minute, black, ovoid seeds about 0.5 in diameter, the structure being 

 apparent only after boiling with chloral solution or solutions of the 

 alkalies. The powder on treatment with a phloroglucin solution 



FIG. 56. Vanilla: S, fragments of seeds showing characteristic stone cells; B, 

 parenchyma cells with narrow-elongated simple pores; P, parenchyma con- 

 taining oil globules; T, tracheae; L, lignified cells with simple pores; Ca, 

 raphides of calcium oxalate; H, papillae-like hairs from the inner surface of 

 the pericarp which are occasionally seen massed together. 



and sulphuric acid assumes a deep red color, due to the presence of 

 vanillin. 



The powder is frequently admixed with tonka, which is easily 

 determined by the presence of starch grains. Some of the so-called 

 vanilla powders are mixtures containing vanillin or coumarin but 

 none of the tissues of either vanilla or tonka. 



