^s^ptember!'^92o; }  United  States  Pkarmacopoeial  Revision.  647 
impossible  to  standardize  the  product  by  both  methods  when  the 
results  obtained  by  one  do  not  parallel  those  obtained  by  the  other. 
We  therefore  recommend  that  the  pharmacodynamic  test  be 
made  compulsory  in  place  of  the  chemical  test,  or  that  a  double 
standard,  i.  e.,  a  chemical  standard  within  a  certain  range  to  guard 
against  excessive  toxicity  and  also  a  minimum  biologic  standard 
(a  MX.D.),  to  guard  against  inactive  or  deteriorated  preparations 
be  adopted  and  that  preparations  which  do  not  conform  to  both 
standards  be  rejected. 
Digitalis-Strophanthus -Squill. — ^The  principal  criticism  of  the 
method  as  given  in  the  Pharmacopoeia  is  in  regard  to  the  tech- 
nique as  recommended  for  injecting  the  doses  into  the  frogs. 
The  U.  S.  P.  states: 
"After  the  frogs  have  been  weighed  as  described,  the  doses  to 
be  given  are  calculated  according  to  their  weights  and  are  measured 
into  small  conical  glasses  by  means  of  a  finely  graduated- pipette.  The 
doses  of  the  preparation  which  are  to  be  injected  should  be  as  uni- 
form in  quantity  as  possible  and  should  not  exceed  0.015  Mil.  for  each 
gram  of  body  weight  of  frog  When  the  doses  are  ready, 
they  may  be  injected  into  the  anterior  lymph  sac  of  the  animal. 
This  is  done  by  means  of  a  glass  pipette  which  is  drawn  out  to  a  fine 
point.  The  frog  is  held  on  its  back  in  one  hand  and  the  pipette 
with  the  contained  drug  in  the  other,  the  mouth  of  the  frog  is  opened 
with  the  point  of  the  pipette  and,  carefully  avoiding  the  tongue, 
the  floor  of  the  mouth  is  punctured  and  the  point  of  the  pipette  is 
then  seen  to  enter  the  anterior  lymph  sac  of  the  frog.  The  contents 
of  the  pipette  are  now  forced  into  the  sac  either  by  gravity  or  by 
gently  blowing,  if  necessary.  In  the  latter  case,  care  should  be  taken 
not  to  introduce  air  into  the  sac." 
It  is  absolutely  impossible  to  obtain  accurate  results  if  this  tech- 
nique is  followed.  It  will  be  noted  that  the  average  frog  should 
weigh  20  Gm.  and  that  the  dose  injected  should  not  exceed  0.015 
Mil.  for  each  gram  or  0.3  Mil.  for  a  20  Gm.  frog.  You  are  directed 
to  measure  this  0.3  Mil.  by  means  of  a  finely  graduated  pipette  into 
a  conical  glass.  This  very  small  dose  (0.3  Mil.)  is  then  sucked  up 
into  another  sharp-pointed  pipette  and  forced  into  the  lymph  sac 
by  blowing. 
The  error  due  to  the  amount  of  solution  left  in  the  conical  vessel 
and  the  second  pipette  is  indeed  great  when  compared  with  the  very 
small  dose  given. 
