3 18  Epinephrin  and  its  Compounds.        { Am  jJu^ifo3arm' 
0*1520  gramme  substance  dissolved  in  very  dilute  hydrochloric  acid  and 
precipitated  with  barium  chloride  gave  0*0746  BaS04  ;  therefore,  H2SO^  = 
2o'59  Per  cent. 
It  will  thus  be  seen  that  a  perfectly  defi?iite  compound  of  the  formula 
C10H13NO3  can  be  made  in  any  desired  quantity  from  the  compou?id, 
C10H13NO3J^H2O.  The  dehydrated  molecule  still  behaves  in  the 
same  way  toward  ferric  chloride,  silver  nitrate,  copper  sulphate,  etc., 
but  has  taken  on  a  new  set  of  properties,  viz.:  alkaloidal  character- 
istics. As  this  substance,  in  the  fottn  of  its  monobenzoyl  compounds, 
has  long  been  known  as  epinephrin,  it  seems  allowable,  in  view  of  the 
analytical  proofs  here  furnished  and  the  relationships  that  have  been 
established,  to  give  to  the  crystalline  form,  C10H13NO3^H2O,  known 
in  its  less  pure  form  as  adrenalin,  suprarenin,  etc.,  the  name  epinephrin 
hydrate. 
The  analytical  data  here  given  show  that  the  formula  C10HnNO3, 
which  I  have  long  maintained  as  representing  the  true  composition 
of  alkaloidal  epinephrin,  is  to  be  changed  to  C10HlsNO3.  That  I 
made  this  small  error  in  the  formula  is  due  solely  to  the  fact  that 
my  earlier  preparations  were,  as  a  rule,  dried  at  too  high  a  tem- 
perature. I  have  observed,  for  example,  that  the  sulphate  just 
described  when  dried  in  vacuo  at  100°  loses  hydrogen  and  shows  a 
higher  carbon  content,  and  if  then  analyzed  will  apparently  have 
the  composition  (C10HnNO3)2H2SO4,  at  least  in  respect  to  carbon, 
hydrogen  and  nitrogen. 
The  formula  of  monobenzoyl  epinephrin  must  therefore  also  be 
changed  from  C17H15N04  —  (C10H10NO3  .  C6H5 .  CO)  to  C17H17NO,  — 
(C10H12NO3  .  C6H5  .  CO).  At  least  one  compound  of  the  monoben- 
zoyl series  is  stable  enough  to  endure  a  drying  temperature  of  100° 
C,  and  in  this  instance  it  is  found  that  no  change  in  the  formula 
need  be  made.  I  refer  to  the  phenyldicarbamic  ester  of  mono- 
benzoyl epinephrin  which  was  briefly  described  in  an  earlier  com- 
munication.1 This  ester  was  made  from  the  sulphate  of  monoben- 
zoyl epinephrin,  and  the  numerous  chemical  stages  through  which 
the  compound  was  made  to  pass  guarantees  its  chemical  individual- 
ity and  purity. 
The  following  analyses  of  its  sulphate  further  fortify  the  formula, 
lAmer.  Jour,  of  Physiology,  Vol.  Ill,  1900;  Proc.  Amer.  Physiol.  Soc,  p.  xvii; 
Johns  Hopkins  Hospital  Bulletin,  Vol.  XII,  1901,  p.  342. 
