Am.  Jour.  Pharm.  ) 
February,  1914.  j 
Standardisation  of  Heart  Tonics. 
67 
Guinea  Pig  Method. 
Reed  and  Vanderkleed  20  first  advocated  the  advantages  of  using 
the  guinea  pig  as  the  test  animal  although  Houghton  13  had  pre- 
viously tried  pigs  but  considered  the  frog  test  more  reliable. 
The  closer  biologic  relation  of  the  guinea  pig  to  man  appears  to 
be  one  important  reason  for  preferring  guinea  pigs.  It  is  claimed  21 
that  "  frogs  not  only  show  the  pharmacological  action  of  the  drug 
under  test,  but  they  react  with  so  near  an  approach  to  uniformity  that 
the  medicinal  value  of  a  tested  specimen  can  be  gauged  by  the  deter- 
mination of  the  minimum  fatal  dose — for  the  slowing  of  the  heart 
beat  and  the  systolic  emphasis  produced  by  active  heart  tonics  are 
directly  proportioned  to  the  quantity  of  the  drug  administered,  and 
under  progressive  doses  at  last  reach  a  point  which  is  incompatible 
with  life." 
Details  of  Reed  and  Vanderkleed  Method  for  Testing  Digitalis 
and  its  Preparations. 
If  Digitalis  leaves  are  to  be  tested  a  tincture  is  first  prepared 
from  the  sample  by  the  U.  S.  P.  process. 
An  amount  of  any  alcoholic  preparation  representing  one-tenth 
of  a  gramme  of  Digitalis  Leaves  is  placed  in  a  very  small  watch  glass 
and  the  excess  of  alcohol  evaporated  from  it  at  room  temperature 
by  placing  the  vessel  in  a  current  of  air.  This  residue  is  then  care- 
fully washed  into  a  Hitchen's  syringe  22  with  sufficient  physiologi- 
cal salt  solution  to  make  the  total  volume  two  cubic  centimetres. 
The  hypodermatic  needle  is  previously  sealed  with  sufficient  petro- 
latum to  prevent  loss  of  this  solution. 
Two  cubic  centimetres  of  physiological  salt  solution  is  placed  in 
the  side-arm  of  the  syringe  and  the  needle  inserted  under  the  skin 
of  a  guinea  pig  weighing  about  250  gm. 
The  solution  of  the  drug  is  then  injected  and  the  last  portions 
washed  under  the  skin  with  the  physiological  salt  solution  which  was 
placed  in  the  side  arm,  without  removing  the  needle. 
Great  precaution  is  taken  to  inject  accurate  amounts  and  always 
a  total  of  four  cubic  centimetres  of  liquid  (2  c.c.  of  solution  of  drug 
and  2  c.c.  of  physiological  salt). 
After  the  injection,  the  guinea  pig  is  kept  under  close  obser- 
vation and  evidences  and  time  of  salivation,  purgation  and  convul- 
sions noted.  If  the  pig  should  not  develop  these  symptoms  and  die 
within  two  hours,  another  pig  is  injected  with  a  larger  quantity  of 
the  drug. 
