302  Epinephrin  and  its  Compounds.  {Am/ui?ri9Po3arm* 
1895,  that  a  very  minute  amount  of  an  aqueous  extract  of  the 
medulla  of  the  gland  will  raise  the  arterial  pressure  to  an  extraor- 
dinary degree.  Interest  in  the  subject  of  internal  secretion  was  at 
this  time  at  its  height.  Pellacani  and  his  pupils  had  studied 
the  effects  of  the  injections  of  extracts  of  the  gland  in  1879; 
others  followed,  but  Schafer  and  Oliver  were  the  first  to  test 
the  effects  of  extracts  on  the  arterial  pressure.  As  early  as 
1885,  Krukenberg1  had  declared  that  the  substance  which  gives 
the  green  color  with  ferric  chloride  is  not  the  chromogenic 
substance  of  Vulpian,  but  more  likely  pyrocatechin  accompanying 
the  chromogen.  From  this  time  on,  the  opinion  that  pyrocatechin 
is  present  in  the  gland  gained  a  firm  hold.  Brunner2  found  that  an 
alcoholic  extract  of  the  gland  can  be  made  to  give  nearly  all  of  the 
reactions  of  pyrocatechin ;  thus,  it  gives  the  well-known  green 
color  with  ferric  chloride,  passing  into  a  fine  red  on  the  addition  of 
ammonium  tartrate  and  a  few  drops  of  an  alkali;  it  reduces  silver 
nitrate  at  room  temperature  and  Fehling's  solution  on  boiling.  The 
addition  of  an  alkali  soon  causes  it  to  take  on  a  dark-brown  color ; 
lead  acetate  gives  a  precipitate ;  sodium  nitroprusside  and  very 
dilute  ammonia  give  a  wine-red  color.  All  of  the  above  reac- 
tions being  given  also  by  pyrocatechin,  Brunner  concluded  that 
Krukenberg  was  right  in  his  belief  that  pyrocatechin  is  present  in 
the  suprarenal  gland. 
Again,  in  1896,  after  it  was  known  that  the  gland  contained  a 
blood-pressure-raising  constituent,  Miihlmann8  returned  to  the  pyro- 
catechin theory,  but  modified  it  so  far  as  to  state  that  pyrocatechin 
is  not  present  as  such  in  the  gland,  but  in  a  form  of  combination 
with  the  active  principle,  from  which  it  may  be  split  off  by  boiling 
with  dilute  hydrochloric  acid. 
It  will  be  seen  that  at  this  time  there  was  a  great  diversity  of 
opinion  as  to  the  chemical  character  of  the  blood-pressure-raising 
constituent.  Xo  one  had  proved  the  existence  of  pyrocatechin  in  the 
gland,  either  as  such  or  in  combination  with  the  active  principle,  by 
such  irrefutable  evidence  as  precipitation  with  lead  acetate  and 
analysis  of  the  lead  compound  thus  obtained,  and  no  one  had  even 
1  Arch.  f.  path.  Anal.,  Bd.  CI  (18S5),  pp.  542-591. 
2 Schweiz.  Wochenschr.,/.  Pharmacie,  Bd.  XXX,  1S92,  pp.  121-123. 
3  Deutsche  med.  IVochenschr,  1896,  Xo.  26,  pp.  409-411. 
