A  jamm?yPi903m'}        Tinctures  of  Potent  Remedies.  21 
always  been  to  use  as  weak  a  menstruum  as  is  possible  to  exhaust 
the  drug,  and  still  have  an  elegant  and  stable  preparation. 
The  advantage  that  must  be  admitted  in  favor  of  the  proposed 
international  standard  menstruum  is,  that  it  would  be  uniform  in 
strength  for  all  tinctures  of  active  drugs  that  are  made  by  percolation. 
In  addition  to  this,  the  keeping  qualities  of  the  preparations  them- 
selves would  be  enhanced  on  account  of  the  increase  in  alcohol  con- 
tent,  and  also  because  a  menstruum  of  comparatively  strong  alcohol 
does  not  extract  as  much  inert  and  useless  material  as  one  contain- 
ing more  water.  In  addition  to  this,  the  strength  of  these  various 
preparations  is  of  such  a  nature  that  it  is  comparatively  easy  to 
exhaust  the  different  drugs  by  percolation  with  the  directed  men- 
struum. 
Before  reviewing  the  different  preparations  before  us,  it  may  be  of 
interest  to  call  attention  to  several  general  points  that  occurred  to 
us  while  making  the  following  samples.  It  is  well  known  that  air- 
dry  drugs  contain  a  variable  amount  of  water,  and  that  this  can  in 
turn  be  displaced  by  prolonged  drying  at  a  comparatively  high 
temperature.  To  get  at  an  approximate  idea  of  the  net  loss  of  ex- 
tractive, a  sample  of  each  drug  was  dried  in  a  steam-box  at  a  uni- 
form temperature  of  6o°  C,  until,  after  two  hours  interval,  there 
was  no  perceptible  difference  in  weight.  The  same  procedure  was 
later  adopted  with  the  exhausted  drug.  The  gross  loss  is,  therefore, 
the  difference  in  weight  between  the  air-dry  drug  and  the  residue 
dried  to  constant  weight,  while  the  net  loss  is  the  estimated  dif- 
ference between  the  air-dry  drug  minus  the  per  cent,  loss  on  drying, 
and  the  residue  dried  to  constant  weight. 
The  difference  in  the  amount  of  contained  water  is  also  of  inter- 
est. Several  experiments  were  made  with  each  of  the  different 
drugs,  and  the  averages  only  are  given.  In  looking  over  the  results 
given  below  it  will  be  found  that  the  highest  loss  was  in  the  case  of 
aconite  root,  while  the  lowest  was  in  powdered  opium.  Several 
samples  of  powdered  opium  that  were  examined  did  not  vary  more 
than  I  per  cent  of  their  weight,  even  on  exposure  to  the  heat  of  the 
drying  oven  for  considerable  length  of  time.  It  will  readily  be  seen, 
however,  how  important  a  factor  this  contained  moisture  might  be. 
In  subsequent  discussions  of  the  international  commission  this 
feature  will,  no  doubt„  be  given  proper  attention  and  provisions 
made  for  eliminating  possible  sources  of  error. 
