Am'tjfiiy r \$Arm' }     Chemistry  of  Pressor  Compounds.  305 
so  that  Popielski  suspected  barium  to  be  present  in  one  of  the  prepa- 
rations. 
Zunz 50  has  also  found  that  so-called  hetero-albumose,  thio- 
albumose,  deutero-albumose,  and,  especially,  proto-albumose  pro- 
duced a  rise  in  blood-pressure  in  dogs  and  rabbits.  This  rise  was 
followed  by  a  marked  fall,  but,  in  the  case  of  the  proto-albumoses, 
large  amounts  were  necessary  to  produce  the  fall.  Witte's  pepton 
has  been  shown  to  exert  both  a  vaso-constrictor  and  a  vaso-dilator 
action.57  Those  products  of  digestion  which  gave  no  biuret  test 
caused  a  marked  fall  in  blood-pressure.  These  differences  in  re- 
sults may  really  be  due  to  a  difference  in  the  kind  of  proto-albumose 
or  hetero-albumose  used,  as  we  have  no  positive  proof  that  all  fibrin 
from  which  Witte's  pepton  is  obtained  has  necessarily  the  same 
chemical  composition.  Proto-albumose  and  syn-albumose  caused 
recovery  of  the  exhausted  isolated  heart,  while  peptons  caused  sys- 
tolic stoppage. 
Loeper  and  Esmonet 58  have  found  that  a  weak  solution  of  what 
is, called  pepsin  caused  a  slight  fall  in  blood-pressure,  followed  by  a 
rise.  This  rise  was  especially  marked  if  the  pepsin  was  treated 
with  hydrochloric  acid,  and  Popielski 59  noted  that  a  hydrochloric 
acid  preparation  of  the  thymus  gland  would  produce  a  rise  in  blood- 
pressure  with  a  slowed  heart,  and,  like  pituitary  preparations,  pro- 
duced this  rise  even  after  section  of  the  spinal  cord.  This  substance 
was  not  precipitated  by  phosphotungstic  acid,  lead  acetate,  or  by 
platinum  chloride  in  alcoholic  solution,  but  was  precipitated  from 
absolute  alcohol  by  an  absolute  alcoholic  solution  of  mercuric  chlo- 
ride. 
From  this  data  we  argued  that  some  of  the  pressor  activity  was 
due  to  a  compound  with  high  molecular  weight ;  that  is,  one  closely 
allied  to  the  proteins  and  which  would  not  dialyse.  Schaefer  and 
Herring  claimed  that  the  pressor  compound  of  the  pituitary  would 
56  Zunz,  E.,  "  Untersuchungen  ueber  die  Wirkung  von  Albumosen  auf 
Blutdruck  und  Atmung,"  Archives  internat.  de  Physiol.,  vol.  n,  p.  73 ;  "  Ueber 
die  Wirkung  von  Albumosen  auf  das  isolierte  ueberlebende  Schildkroten 
Herz,"  Ibid.,  vol.  10,  p.  290. 
57  Kaufmann,  P.,  "  Ueber  die  Wirkung  des  Witte-Peptones  auf  die  Blut- 
gefasse,"  Zent.  f.  Physiol.,  vol.  27,  p.  724  (1913). 
B8  Loeper  and  Esmonet,  "  Action  vaso-tonique  comparee  des  different  pro- 
duite  de  secretion  gastrique,"  Comp.  rend.  Soc.  de  Biol.,  vol.  70,  p.  8  (1911). 
69  Popielski,  L.,  "  Ueber  eine  neue  blutdrucksteigernde  Substanz  des 
Organismus,"  Zent.  f.  Physiol.,  vol.  23,  p.  137  (1909). 
