^"•iugusri?2^:  I         Methods  for  Digitalis  Assay.  537 
so  that  powerful  drugs  can  be  standardized  although  possessing  no 
chemical  reactions  by  which  their  values  can  be  determined. 
The  scope  of  each  is  distinctly  defined,  the  assay  process  being 
subordinate  to  and  based  entirely  on  the  pharmacology  of  the  drug 
in  question. 
The  criticisms  of  the  biologic  assay  process  in  general  are  really 
without  material  basis  since  it  is  strictly  analogous  to  the  chemical 
assay.  Neither  assay  method  attempts  to  encroach  on  the  clinical 
application  of  a  drug  but  concerns  itself  only  with  the  potency. 
Both  make  use  of  the  reaction  which  most  accurately  determines 
the  amount  of  active  agent  present  by  use  in  the  one  case  of  chemical 
reagents,  in  the  other  of  the  animal  least  subject  to  variations. 
Digitalis,  therefore,  as  one  of  the  most  valuable  drugs  at  the 
command  of  the  physician,  cannot  be  permitted  to  pass  without 
standardization . 
The  selection  of  the  method  should  be  based  on  the  most  typical 
effect  which  is  measurable  and  which  is  subject  to  the  least  variation 
that  is  beyond  the  control  of  the  operator. 
BIBLIOGRAPHY. 
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^2  Reed  and  Vanderkleed:    Am.  J.  Pharm.,  80:  no,  1908. 
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Parke,  Davis  &  Company, 
Detroit,  Mich. 
