64 
Biological  Standardisation.         {  a^J0^  ^^tu 
such  a  complex  character  that  it  should  be  measured  by  a  standard, 
not  in  any  respect  open  to  criticism.  The  standard,  if  not  identical 
with  the  sample,  should  be  one  whose  composition  and  identity  has 
been  established. 
The  description  of  ouabain  indicates  that  it  is  derived  from  a 
non-official  strophanthus  seed,  that  its  composition  is  indefinite  in 
that  it  crystallizes  with  varying  quantities  of  water  and  that  it  does 
not  yield  a  crystalline  strophanthidin  and  cannot  therefore  be  assayed 
chemically  to  establish  uniformity.  That  it  is  not  uniform  is  shown 
by  Rowe  (6),  a  conclusion  which  may  be  deduced  from  the  fact  that 
the  M.  S.  D.  of  ouabain  accepted  by  the  U.  S.  P.  Committee  is 
.0000005,  while  the  average  of  the  three  samples  tested  by  Rowe  is 
.00000086  or  76  per  cent,  more — a  difference  not  due  to  temperature, 
because  in  all  cases  the  tests  were  carried  out  at  200  C.  Further 
it  is  an  expensive  substance  and  obtainable  only  by  importation. 
These  and  perhaps  other  objections  would  certainly  have  been 
brought  out  by  the  ones  who  must  use  the  test  if  such  an  opportunity 
had  been  granted. 
Strophanthin  from  Kombe  seed  can  be  made  of  uniform  composi- 
tion and  activity  according  to  Brauns  and  Closson  (7)  and  is  there- 
fore preferable  to  ouabain  for  every  reason,  but  its  use  seems  es- 
pecially logical  because  of  being  derived  from  the  official  strophan- 
thus seed. 
Cannabis. 
The  biologic  assay  of  cannabis  indica  is  another  that  is  open  to 
criticism,  not  only  in  the  wording  of  the  text,  but  in  the  size  of  the 
test  dose  and  in  certain  of  its  details. 
As  to  the  words  used,  the  statement  is  made  that  cannabis  "  pro- 
duces incoordination  when  administered  to  dogs  in  a  dose  of  not 
more  than  0.03  mil  of  fluid  extract,  .  .  .  ."  How  much  smaller  dose 
will  show  a  similar,  but  less  marked  effect?  What  is  the  effect  of 
a  larger  dose?  A  logical  wording  would  be  that  Standard  F.  E. 
Cannabis  produces  incoordination  in  a  dose  not  less  than,  etc. 
The  dose  chosen  is  too  small  for  a  satisfactory  test.  The  aver- 
age dog  will  scarcely  react  to  a  dose  of  this  size  and  if  the  drug  is 
somewhat  less  active  than  standard,  the  animal  will  not  react  visibly. 
Under  the  rather  drastic  conditions  imposed,  some  dogs  will  show  the 
effect  of  cannabis  to  a  fairly  satisfactory  degree,  but  a  large  majority 
will  show  the  effect  very  slightly  if  at  all — a  statement  corroborated 
by  Pearson  (8). 
