195 DIGITALIS PUKPUREA 



being also commonly formed later in their life. In the process of 

 flowering the only compounds that are taken up in any amount 

 are those which are concerned in the growth and development 

 of new tissues ; no further growth can therefore take place (to any 

 great extent at least),, in the vegetative organs of a plant, after the 

 flowering stage has commenced ; but the secretions by the removal 

 of these nutritive products become more concentrated, and the 

 organs in which they are produced, by being left for a longer 

 period in connection with the plant, have time to elaborate them 

 more perfectly. 



The leaves should be collected in the second year of the plant's 

 growth, as directly stated in the United States Pharmacopoeia, and 

 also implied in the directions of the British and Indian pharma- 

 copoeias, as the plant does not flower till the second year. But 

 the first year's leaves are frequently substituted for those of the 

 second year's growth ; as are also the leaves of Inula Gonyza, DC., 

 Ploughman's Spikenard, and those of Symphytum offidnale, Linn., 

 Comfrey, Verbascum Thapsus, Linn., Mullein, and other plants ; and 

 as these are sometimes not readily distinguished from the official 

 leaves, it is better for pharmacists to purchase the fresh plant when 

 in flower, which can scarcely be mistaken for any other, and strip 

 and dry the leaves for themselves. 



General Characters and Composition. The botanical characters 

 of the fresh leaves have been already given. When bruised, they 

 have an unpleasant herbaceous odour ; but when dried their odour 

 is agreeable, and resembles tea. The dried leaf has a very bitter 

 taste. Digitalis seeds were formerly official, and are by some pre- 

 ferred to the leaves. 



Digitalis leaves and seeds contain a non-nitrogenised neutral 

 principle called digitalin, to which their properties are essentially 

 due ; but this name has been applied by chemists to widely dif- 

 ferent substances, both crystalline and amorphous, but what relation 

 these substances have to one another, as well as their respective 

 physiological actions, are questions yet to be solved. The digitalin 

 which is official in the British, Indian, and United States 

 pharmacopoeias, as well as in the French Codex, is the Digitalin 



