306  Chemistry  of  Pressor  Compounds.     { Am'ji?y  riSiarm' 
dialyse,  hence  was  not  a  protein.  Using  toluol  as  a  preservative, 
we  lound  tnat  much  of  the  color  dialysed  through  heavy  parchment 
paper,*  and  that  this  colored  solution  was  usually,  though  not  always, 
active,  while  the  liquid  in  the  dialyser  was  intensely  active.  In  this 
connection  it  may  be  remembered  that  Handovsky  and  Pick  showed 
that  there  is  in  the  serum  a  vaso-constrictor  substance  which  is  not 
dialysable  00  and  which  is  not  a  globulin. 
When  our  dialysate  was  collected  in  fractions,  the  last  fractions 
were  without  activity,  whereas  the  fluid  within  the  dialyser  was  still 
very  active,  hence  one  of  the  pressor  principles,  perhaps  the  mother 
substance  of  the  dialysable  pressor  principles,  is  non-dialysable. 
The  depressor  principle  passes  quickly  into  the  dialysate. 
After  long  dialysis  the  residue  in  the  dialyser  gives  a  slight  pre- 
cipitate with  lead  subacetate,  none  with  mercuric  acetate  or  a  solu- 
tion of  iodine  in  potassium  iodide,  but  gives  a  precipitate  with  phos- 
photungstic  acid  or  phospho-molybdic  acid  and  with  stannous  chlo- 
ride or  mercuric  chloride.    It  also  gives  a  strong  biuret  reaction. 
Fuhner  claims  to  have  separated  from  pituitary  extracts  by 
means  of  phosphotungstic  acid  precipitation  and  subsequent  decom- 
position of  the  precipitate  by  means  of  barium  hydrate  various 
pressor  compounds.  On  the  other  hand,  Popielski  claims  that  the 
pressor  activity  is  in  the  phosphotungstic  acid  filtrate.61  Now  it  has 
been  found  that  phosphotungstic  acid  changes  the  chemical  compo- 
sition of  various  compounds,62  hence  there  is  a  possibility  that  phos- 
photungstic acid  would  split  our  non-dialysable  compound  into 
various  amines. 
The  active  non-dialysable  portion  seems  to  correspond  in  some 
respects  to  the  fraction  separated  by  Raper  under  the  name  Ba.63 
*  Note. — Animal  membranes  cannot  be  used  for  dialysis,  as  we  have 
found  that  the  pressor  principles  are  completely  removed  from  the  solution 
by  them  and  cannot  be  recovered. 
60  Handovsky,  H.,  and  Pick,  E.  P.,  "  Ueber  die  Entstehung  vasokon- 
striktorischen  Substanzen  durch  Veranderung  der  Serumkolloide,"  Archiv. 
f.  exper.  Path.,  vol.  71,  p.  62  (1913). 
61  Fuhner,  "  Ueber  die  isolierten  wirksamen  Substanzen  der  Hypophy- 
sen,"  Deutsch.  med.  Woch.,  vol.  39,  p.  491  (1913)  ;  Popielski,  L.,  "Hypo- 
physis und  ihre  Praparate,"  Berl.  klin.  Woch.,  vol.  50,  p.  1156  (1913). 
62 Van  Laer,  H.,  "Nature  of  Amylase,"  Bull.  Acad.  Roy.  Belg.,  vol.  4, 
p.  13;  quoted  in  Chem.  Abstr.,  vol.  8,  p.  510  (1914). 
63  Raper,  H.  S.,  "  Zur  Kenntniss  der  Eiweiss-peptone,"  Beitr.  z.  chem. 
Physiol,  vol.  9,  p.  168  (1907).  See  also  Stookey,  L.  B.,  "Zur  Kenntniss  der 
Eiweisspeptone,"  Beitr.  z.  chem.  Physiol,  vol.  7,  p.  590  (1906). 
