THE PHYSIOLOGICAL STANDARDIZATION OF DIGITALIS. 
By Charles Wallis Edmunds, 
Assistant Pharmacologist, Hygienic Laboratory , U. S. Public Health and Marine- 
Hospital Service , 
and 
Worth Hale, 
Assistant Pharmacologist , Hygienic Laboratory, U. S. Public Health and Marine- 
Hospital Service. 
One of the directions along which scientific medicine has advanced 
during the past few years is in the greater accuracy with which medicines 
are administered. A very essential factor in this tendency is that 
the drugs themselves shall be of a uniform strength, and to insure 
this the Pharmacopoeia of the United States, in its last revision, pro- 
vided a number of standards to which official preparations must con- 
form. Especially is this true in the case of a number of drugs, such 
as opium, belladonna, nux vomica, etc., in which the active constitu- 
ents are capable of isolation in a pure form. With a considerable 
number of others,, however, this w T as not found to be possible for the 
reason that the active principles are either not known or are not 
capable of being isolated in pure state by any known chemical 
method. In this class occur such drugs in common use as digitalis 
and the other members of that series, ergot and cannabis indica. 
By far the most important member of this group is digitalis itself, 
on account of its widespread use in cases of cardiac disease. At the 
present time it is impossible to secure a standardized preparation of 
the drug by any known chemical means * 6 on account of the fact that 
the activity of the drug depends upon no single active principle, but 
upon several wffiose chemistry is not completely known and for the 
isolation of which there does not, at the present time, exist any 
satisfactory chemical method. 
Our knowledge of the chemistry of the digitalis leaves we owe 
mainly to Schmiedeberg and Kiliani. The most important constit- 
uent is digitoxin, a glucoside, which is insoluble in water but soluble 
“Submitted for publication December 4, 1908. 
& Some firms put out preparations standardized so as to contain a certain percentage 
of digitoxin, but, as will be pointed out, this need not indicate a uniform physiological 
activity. 
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