Active  Principle  of  Suprarenal  Gland, 
^Ara.  Jour.  Pharni 
Dorember.  I!)!! . 
Toujan/  the  mercuric  chloride  test  of  Comessati/  and  the  iodic  acid 
reaction  of  Krauss  ^  and  independently  described  by  Frankel  and 
Allers/  were  found  to  be  much  more  delicate.  The  suggestion  of 
Abel  ^  that  the  fleeting  green  color  produced  by  ferric  chloride 
could  be  rendered  more  permanent  by  addition  of  an  excess  of 
potassium  benzene  thiosulphonate  was  not  followed  up  since  the 
ferric  chloride  test  is  of  such  general  applicability  that  it  was 
thought  to  be  less  characteristic  of  the  epinephrine  base  than  the 
three  tests  mentioned  above. 
According  to  the  iodine  test  of  Abelous,  Soule  and  Toujan,  lo 
c.c.  of  the  1 :  10,000  epinephrine  solution  is  mixed  with  5  c.c.  of  o.i 
n  iodine  and  allowed  to  stand  15  minutes,  the  excess  of  iodine  is 
then  discharged  with  o.i  n  thiosulphate,  the  solution  diluted  to  50 
c.c.  and  its  color  compared  with  standards  made  in  the  same  way 
with  a  solution  of  the  pure  base.  Experiments  showed,  however, 
that  the  intensity  of  the  pink  color  increased  with  length  of  time 
allowed  before  the  discharge  of  excess  of  iodine ;  moreover,  the 
tints  varied  to  such  an  extent  that  accurate  comparison  did  not 
appear  possible,  and  all  the  colors  faded  fairly  rapidly  on  standing. 
With  the  mercuric  chloride  test  which  consists  in  adding  a  few 
drops  of  saturated  HgCL  to  the  epinephrine  solution  and  heating 
to  the  boiling  point,  the  colors  developed  rather  slowly,  and  fur- 
thermore, variations  in  shade  and  intensity  were  obtained  from 
equal  amounts  of  the  active  principle.  The  most  satisfactory  results 
were  obtained  with  the  iodic  acid  test,  viz.,  by  heating  just  to 
boiling,  the  mixture  of  equal  parts  of  the  solution  to  be  tested  and 
0.2  per  cent.  KIO3  solution.  The  addition  of  a  few  drops  of  dilute 
phosphoric  acid  as  prescribed  by  Frankel  and  Allers  was  found  to  be 
a  disadvantage  since  it  caused  much  more  rapid  fading  of  the  color. 
Using  a  standard  epinephrine  solution  containing  i  part  per  50,000 
of  the  pure  base  dissolved  with  the  aid  of  twice  the  calculated 
amount  of  HCl  to  yield  the  hydrochloride,  the  pink  color  was  found 
to  remain  practically  unchanged  for  several  days. 
Although  the  color  produced  as  above  mentioned  is  fairly  stable 
and  would  undoubtedly  serve  as  a  standard  with  which  to  compare 
^  Compt.  rend.  soc.  hiol,  58,  301,  1905. 
Arch.  Exp.  Path.  u.  Pharm.,  62,  190,  1909-10. 
^Apoth.  Ztg.,  23,  70,  1908. 
*  Biochem.  Ztschr.,  18,  40,  1909. 
^  Johns  Hopkins  Hosp.  Bull.,  12,  342,  1901. 
