CRUDE DRUGS. 



615 



Leaves that are more than 30 cm. long should be rejected, as 

 also the tuft of radical leaves of the first-year plant. 

 Inner Structure. See Fig. 266. 



Fig. 266. Transverse section of digitalis leaf through one of the veins: UE, uppe 

 epidermis; P, mesophyll; LE, lower epidermis; G, glandular hairs; N, non-glandular hairs; 

 C, coUenchyma; T, tracheae; S, sieve. 



Constituents. Several crystalline glucosides, including digi- 

 toxin (0.2 to 0.3 per cent.), digitalin and digitonin, the former 

 two being the more important. The drug also contains a volatile 

 oil containing a stearoptene digitalosmin, which has the odor of 



