348 PHARMACOPEIAL DRUGS 



matic flavor, commands the highest market price. 

 Mr. Beringer describes it as follows: 



"Prime Mexican vanilla is from eight to ten inches 

 long, flattened, and about three-eighths of an inch in 

 diameter at the broadest part. Its upper end or end of 

 attachment tapers gradually for about one-quarter of 

 the length of the pod, and is usually curved and slightly 

 twisted toward the point. The lower end is but very 

 slightly attenuated. The color is a dark brown, and 

 the odor is pleasant, aromatic and characteristic. The 

 surface is ridged longitudinally, the ridges being inter- 

 spersed with finer striations and warty excrescences. 

 The pods feel firmly plump, and while fresh the surface 

 is somewhat viscid, but nevertheless there is a roughness 

 to the touch which becomes more pronounced as it gets 

 older and dryer. Acicular crystals commence to form 

 at the ends, and gradually extend over the surface. 

 The interior is filled with numerous black seeds and a 

 small quantity of pulp." 



The crystals covering vanilla beans that have been 

 cured are called "frost." Until 1859 they were be- 

 lieved to consist of benzoic add, but in that year Gobley 

 established its distinction from that substance, and 

 gave it the name vanillin, believing that in this sub- 

 stance was found the aromatic principle of vanilla. 

 However, the subsequent artificial production of vanil- 

 lin has not been able to displace the use of the beans. 

 Neither has the amount of the vanillin present in va- 

 nilla beans been accepted as a criterion of their quality. 

 Suffice it to say that the best Mexican vanilla has been 

 found to contain only 1.69 per cent vanillin, while 

 Bourbon contained 2.48, and Java 2.75 per cent va- 

 nillin. Sometimes benzoic acid is dusted over an in- 



