102  Standardization  of  Digitalis  Bodies,  j 
Am.  Jour.  Pharm. 
March,  1913. 
Maximum  variation 
Exp.                        Drug  Dose  in  Mg.     Average  from  average  in 
X  kg.  per  cent. 
Adonidin — Cont'd. 
2  4.28 
3  5- 10  4-34  17-4% 
4  3-58 
5  5-00 
Helleborein 
1  1.66 
2  1.70  1.88  31.3% 
3  2.47 
4  1-72 
Digitalein 
1  3-7 
2  3.2 
3  3-5  3-47  7-7% 
4  3-45 
5  3-5 
Criticisms  and  Comparisons. 
The  first  of  the  desiderata  is  that  the  method  shall  be  reasonably 
accurate  and  give  fairly  concordant  results  on  repeated  tests  of  the 
same  preparation.  Reference  to  the  table  will  immediately  give 
the  idea  that  the  cat  method  fails  in  the  first  and  most  important 
requirement.  Careful  consideration,  however,  will  show  this  to  be 
an  impression  rather  than  a  fact.  For  example,  in  series  A  of 
ouabain  the  maximum  variation  from  the  average  dose  as  deter- 
mined by  the  twelve  tests  is  33.6  per  cent,  of  the  average.  Further, 
each  of  the  starred  experiments  varies  from  the  average  dose 
of  the  series  by  at  least  30  per  cent.  These  are  very  great  variations 
for  a  test  which  is  to  establish  a  standard,  but  if  the  average  of 
the  entire  twelve  be  taken  as  the  result  of  the  standardization  of 
the  specimen,  which  is  in  fact  precisely  what  is  done  in  any  method 
of  biological  assay,  it  will  be  seen  to  lie  only  2  per  cent,  below  the 
average  determined  by  a  very  large  number  of  series  of  tests  made 
over  several  years  (see  H.  &  B.1). 
It  will  be  shown  that  in  this  or  any  other  biological  method  of 
assay  a  certain  number  of  animals  will  be  found  to  be  either  tolerant 
or  susceptible  to  the  action  of  a  given  drug.  Thus,  in  each  of 
several  series  of  experiments  reported  by  Hatcher  and  Brody  1  such 
variations  were  seen  and  from  these  I  will  cite  the  following  ex- 
ample:  Four  cats  received  digitalinum  verum  requiring  1.50, 
1.52,  1.56,  and  1.80  mg.  per  kilogramme,  respectively,  to  cause  death, 
