300  Chemistry  of  Pressor  Compounds.  {Am'/U0iyr'i91i4arm' 
ulable  proteins  by  means  of  heat  and  nitration.  Aqueous  extracts 
of  undried  pituitaries  pass  through  filter  paper  with  the  greatest 
difficulty,  but  after  thorough  coagulation  of  the  proteins  the  extracts 
filter  readily. 
As  Lewis,  Miller  and  Matthews  showed  that  a  pressor  action 
could  be  obtained  from  all  portions  of  the  gland,  we  used  the  whole 
gland  and  avoided  the  tedious  mechanical  labor  of  removing  the 
posterior  portion.  The  fresh  beef  glands  were  ground  in  a  meat- 
chopper and  extracted  twice  with  o.i  per  cent,  acetic  acid,  and,  after 
squeezing  through  cheese-cloth,  the  extract  was  coagulated  on  the 
water-bath  and  the  filtrate  evaporated  in  vacuo.  This  gradually 
colored  during  evaporation  and  left  a  brownish-yellow,  gummy,  non- 
crystalline mass,  which,  on  intravenous  injection  into  dogs,  would 
induce  a  marked  rise  in  blood-pressure. * 
On  treatment  with  hot  methyl  alcohol  (Merck's  highest  purity) 
all  the  color  and  activity  went  into  the  alcohol.  This  solution  gave 
a  heavy  precipitate  on  the  cautious  addition  of  a  drop  or  two  of  con- 
centrated sulphuric  acid,  which  redissolved  with  an  excess  of  the 
acid.  This  precipitate  dissolved  in  water,  forming  a  reddish  solu- 
tion, and  produced  a  marked  rise  in  blood-pressure.  When  freshly 
precipitated  it  dissolved  in  hot  methyl  alcohol  or  ethyl  alcohol  (com- 
mercial 95  per  cent.),  but  if  washed  with  ether  and  placed  in  the 
desiccator  became  insoluble  in  either  alcohol.  At  first  we  believed 
this  to  be  a  true  sulphate  mixed  with  calcium,  but  found  that 
after  further  purification  it  failed  to  be  reprecipitated  from  methyl 
alcohol  by  sulphuric  acid,  hence  we  argued  that  the  first  precipita- 
tion was  merely  mechanical.  This  precipitate,  dissolved  in  water, 
or  the  acetic-acid  extract  of  the  glands,  gave  a  heavy  precipitate 
with  lead  acetate  or  lead  subacetate,  mercuric  chloride  or  uranium 
acetate. 
The  filtrate  after  uranium  acetate  precipitation  was  active,  but 
uranium  gave  no  precipitate  if  the  lead  precipitation  had  been  com- 
pletely done.  Mercuric  chloride  also  gave  a  heavy  precipitate  and 
the  filtrate  was  active.  Gold  chloride,  platinum  chloride,  silver 
acetate,  picric  acid,  picolinic  acid,  and  benzoyl  chloride  with 
sodium  hydrate,  all  gave  precipitates  with  a  solution  of  the  sulphuric- 
*  Note. — These  dogs  were  narcotized  with  ether  and  morphine  and  the 
vagi  nerves  were  usually  cut.  The  most  satisfactory  results  were  obtained 
by  using  young  dogs.    Older  or  large  ones  did  not  seem  to  respond  well. 
