THE  AMEEICAE" 
JOURNAL  OF  PHARMACY 
MAY,  1 91 7 
CONCERNING  THE  U.  S.  P.  STANDARD  FQR  PITUITARY 
EXTRACT  (LIQUOR  HYPOPHYSIS)'.  ' 
By  Charles  R.  Eckler. 
The  United  States  Pharmacopoeia  places  a  physiological  stand- 
ard requirement  for  pituitary  extract  (liquor  hypophysis)  which 
reads  as  follows : 
"  One  mil  of  solution  of  hypophysis,  diluted  20,000  times,  has  the 
same  activity  on  the  isolated  uterus  of  the  virgin  guinea  pig  as  a 
1  : 20,000,000  solution  of  beta-imidazolylethylamine  hydrochloride 
when  tested  as  directed  by  the  United  States  Hygienic  Laboratory." 
Attention  has  been  called  to  the  fact  that  this  is  an  exceedingly 
low  requirement,  but  the  correctness  of  the  figures  in  the  statement 
have  not  been  questioned.  The  results  of  my  work  in  the  subject 
are  so  utterly  at  variance  with  the  pharmacopceial  statement  that  I 
am  prompted  to  question  whether  or  not  the  requirement  as  stated 
is  correct.  My  question  is  this  :  should  the  equivalent  of  1 : 20,000,- 
000  B-imid  be  1  : 20,000  or  1  : 200,000  ?  In  order  to  show  my 
grounds  for  raising  this  question,  I  wish  to  briefly  describe  my 
apparatus  (a  detailed  description  of  which  will  appear  in  another 
paper),  to  give  in  detail  the  method  and  procedure  of  making  the 
dilutions,  together  with  my  results  in  general  as  to  the  relative  ac- 
tivity of  the  two  substances  in  causing  contractions  of  the  isolated 
guinea  pig  uterus. 
Apparatus. 
The  apparatus  used  is  similar  to,  and  was  fashioned  after,  that 
described  by  Dale  and  Laidlaw  (1),  and  is  in  principle  essentially 
like  that  used  by  Roth  (2).  In  consists  of  an  amber-glass,  100  Cc. 
graduated  chamber  for  holding  Locke's  solution,  in  which  the  uterus 
(-95) 
