THE  AMERICAN 
JOURNAL  OF  PHARMACY 
DECEMBER,  igii 
COLORIMETRIC   AND    PHYSIOLOGICAL  ESTIMATION 
OF  THE  ACTIVE  PRINCIPLE  OF  THE  SUPRA- 
RENAL GLAND. 
By  Worth  Hale  and  Atherton  Seidell. 
[Hygienic  Laboratory,  U.  S.  Public  Health  and  Marine-Hospital  Service, 
Washington,  D.  C] 
Of  the  many  color  tests  which  have  been  proposed  for  the  active 
principle  of  the  suprarenal  gland,  none  appears  to  have  been  devel- 
oped to  the  accuracy  required  of  a  quantitative  method.  Several 
have  been  used  for  comparative  studies  on  glands  from  different 
sources,  but,  so  far  as  shown  by  the  literature,  no  attempts  have 
been  made  to  correlate  the  results  obtained  by  color  tests  with  the 
activity  as  determined  by  physiological  methods. 
In  applying*  a  number  of  the  better  known  color  reactions  to 
a  series  of  desiccated  suprarenal  glands,  for  the  purpose  of  selecting 
a  suitable  one  for  the  forthcoming  revision  of  the  U.  S.  Pharma- 
copoeia, it  was  noticed  that  considerable  variation  in  the  intensities 
of  the  colors  froii  the  several  samples  was  obtained;  preliminary 
blood  pressure  experiments  with  some  of  these  samples  confirmed 
the  differences  indicated  by  the  color  tests.  It  thereupon  appeared 
probable  that  a  colorimetric  method  which  would  yield  results  in 
close  agreement  with  those  obtained  by  the  physiological  standardiza- 
tion, could  be  developed. 
Experiments  with  the  various  color  tests  which  have  been  pro- 
posed, indicated  that  the  potassium  permanganate,  the  potassium 
ferricyanifle  with  dilute  ammonia,  the  sodium  hydroxide,  and  the 
potassium  permanganate  with  lactic  acid,  reagents,  gave  little 
promise  of  success.    The  iodine  method  of  Abelous,  Soule  and 
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