^ Ap°rn; i9oTm*}     Contributions  from  H.  M.  Gordin.  163 
air  should  therefore  be  avoided  as  much  as  possible.  As  it  is 
impossible  to  exhaust  some  drugs  like  nux  vomica,  ipecac  and  cin- 
chona without  the  use  of  acids,  only  very  dilute  acids  should  be 
used. 
The  standard  method  might  vary  from  drug  to  drug,  but  in  no 
case  shall  any  method  be  adopted  as  a  standard  unless  it  possesses 
the  above-mentioned  features.  As  we  have  to  admit  that  a  method 
which  gives  good  results  upon  one  sample  of  a  drug  will  give  equally 
good  results  with  any  other  sample  of  the  same  drug,  provided  the 
samples  are  in  the  same  condition  of  fineness,  etc.,  we  can  establish 
by  means  of  the  standard  method  the  actual  amount  of  alkaloid  in 
a  given  drug  as  exactly  as  it  is  possible  at  present,  and  then  try 
different  expedient  methods  until  we  find  one  which,  being  simple 
and  expedient,  gives  results  which  are  the  same  or  very  nearly  the 
same  as  those  obtained  by  the  standard  method.  Should  there  not 
be  such  a  simple  method,  we  can  adopt  any  desirable  method  and 
introduce  a  definite  correction  into  our  results. 
With  these  principles  in  mind,  I  started  to  apply  the  ideas  here 
developed  to  a  few  of  the  more  important  medicinal  drugs.  Among 
the  drugs  chosen,  some  are  very  easily  affected  by  strong  reagents, 
but  easily  exhaustable  (coca),  others  are  quite  stable  in  presence  of 
reagents  but  are  very  difficult  to  exhaust  (nux  vomica),  and  again 
others  are  both  easily  affected  and  difficultly  exhausted  (ipecac). 
As  my  intention  was  not  to  compare  most  of  the  proposed  methods 
with  each  other,  but  only  to  find  one  among  them  which  gives 
results  approaching  sufficiently  near  those  of  the  standard,  I  shall 
not  record  a  large  number  of  experiments  with  many  methods 
which  proved  not  to  answer  the  above  requirement,  but  shall  give 
briefly  the  positive  results  and  how  they  were  obtained.  In  every 
case  I  first  established  a  standard  method  and  then  tried  to  find  a 
suitable  substitute  for  this  method.  Should  any  other  more  expedient 
method  be  found,  it  might  easily  be  adopted,  providing  its  results 
are  not  far  from  those  of  the  standard. 
The  most  expedient  seem  to  me  to  be  the  following  two  methods, 
which  I  shall  call  method  A  and  method  B.  As  one  or  the  other 
of  these  two  methods  has  given  very  good  results  as  compared  with 
the  standard  method  in  the  case  ot  the  drugs  tried,  I  have  not  con- 
sidered any  other  method,  but  it  is  possible  that  in  the  case  of  other 
drugs  some  other  method  might  give  results  even  more  concordant 
with  those  obtained  with  the  standard  method. 
