DIGITALIS 



619 



containing freshly burnt lime is placed, the latter container being 

 covered with perforated parchment, but Hatcher's work would seem 

 to show that this is unnecessary. Again, it is frequently empha- 

 sized that the leaves should not be kept longer than one year, but the 

 drug may be kept indefinitely, if the leaves have been carefully 

 selected, properly dried and stored. Newcomb and Rogers found 

 that the petioles of Digitalis were from one-fourth to one-fifth as 

 active as the entire leaf. The active principles are in the cells within 



FIG. 272. Cultivation of Digitalis: A general view of the Experimental Farm of 

 Eli Lilly & Co. showing the testing and breeding of various species and 

 varieties of Digitalis. After Miller, Amer. Jour. Pharm., 1913, p. 298. 



the leaf and apparently not developed in the hairs. The quality of 

 digitalis is improved by separating the dirt siftings as much as 

 possible. Most of the commercial supplies were obtained from Eng- 

 land, Austria, Hungary, and the Harz and Vosges mountains of 

 Europe, but much of the drug is now produced in the United States. 

 In a study on the effect of temperature on drying digitalis leaves 

 Hamilton (Amer. Jour. Pharm., 1919, 91, p. 177), obtained the fol- 

 lowing results. 



