It is generally recognized that the infusion of digitalis deteriorates rapidly; in fact, it is often stated that digitalis and all of its preparations undergo rapid changes. Several pharmacopeias, notably the German, French and Swiss, direct that the leaf shall not be kept longer than one year despite the utmost care in its preservation.
We have shown1 that when the leaves are kept with the least care for periods up to twenty-five years, they retain a degree of activity equal to that of fresh leaves of good quality, and that a fluidextract made thirty years previously was quite as active as one of good quality recently made.
Digitalis is not completely exhausted in making the infusion by the official process, in which the bruised leaf is directed; hence this process was modified slightly and the infusions used in the present investigation were made as follows: Powdered digitalis of good
HATCHER RA, EGGLESTON C. THE STABILITY OF THE INFUSION OF DIGITALIS. JAMA. 1915;LXV(22):1902-1905. doi:10.1001/jama.1915.02580220042013