138  Estimation  of  Ash  in  Various  Drugs.  {^^Xm™- 
as  in  one  case  which  came  under  the  author's  notice,  the  percentage 
of  ash  present  in  a  certain  drug  was  stated  as  "  about  8  per  cent.;" 
and,  as  authentic  samples  collected  by  the  author  gave  a  maxi- 
mum of  5-20  per  cent.,  and  the  highest  amount  in  the  commercial 
drug  was  3-42  per  cent.,  the  accuracy  of  the  authority  quoted  is 
questionable. 
Some  scattering  contributions  to  this  subject  have  been  made  in 
the  past  few  years,  but  in  most  cases  the  data  are  incomplete  in 
some  one  respect.  It  is  a  matter  of  surprise  to  note  what  little 
importance  has  been  attached  to  the  moisture  in  the  sample  taken 
for  estimation.  It  is  obvious  that  the  moisture  content  varies  with 
the  atmospheric  changes  to  which  the  drug  is  exposed,  and  that 
the  only  reliable  basis  for  comparison  is  the  per  cent,  of  ash  calcu- 
lated to,  or  estimated  in,  the  moisture-free  substance. 
The  therapeutic  activity  of  any  given  drug  is  attributable  to  the 
constituents  peculiar  to  that  drug,  irrespective  of  the  physiological 
effects  produced  by  so-called  inert  cellular  tissue.  It  might,  there- 
fore, truthfully  be  said  that :  The  therapeutic  effect  of  any  given  drug 
is  the  algebraic  sum  of  the  effects  of  its  proximate  constituents.  Effect 
is  used  in  a  relative  sense  only  ;  no  uniform  or  fixed  value  can  be 
given,  in  view  of  the  fact  that,  in  no  two  cases  of  administration,  are 
the  conditions  exactly  similar.  The  inorganic  constituents  may  play 
a  very  small  part  in  the  physiological  action  of  a  drug,  but,  in  the 
present  state  of  our  knowledge,  no  factor,  however  slight,  should 
be  ignored. 
Certain  groups  of  plants  show  marked  peculiarities  in  the  amount 
of  ash  present.  The  leaves  of  those  plants  belonging  to  the  Natural 
Order  Solanaceae  are  noted  for  the  large  amount  of  inorganic  mat- 
ter present ;  in  some  instances  over  25  per  cent.,  or  more  than 
one-fourth  their  weight,  is  obtained  as  ash,  upon  ignition  of  a 
sample. 
This  work  was  begun  for  the  purpose  of  collecting  data  on  a 
number  of  the  more  commonly-used  drugs,  with  the  hope  that  they 
might  be  found  of  service  in  subsequent  studies  concerning  identifi- 
cation of  drugs.  The  subject  proved  to  be  one  of  great  interest, 
and  the  results  accompanying  the  present  paper  are  published  with 
the  idea  that  by  making  occasional  contributions  of  a  limited  num- 
ber each  time,  the  tedium  of  a  long,  uninteresting  list  (dry  reading 
at  its  best)  would  be  avoided,  and  also  that  others  who  are  in  a  po- 
