562  Preparations  of  Aconite.  {'^'"^£'"'"'188^'"* 
of  the  strength  is  also  adopted.  Of  course,  the  taste  or  impression 
as  a  measure  of  strength  cannot  pretend  to  be  very  accurate,  nor  indeed 
accurate  at  all,  but  it  is  a  very  useful  measure,  and  will  serve  all  the 
practical  purposes  of  the  physician  and  the  pharmacist.  It  is  very 
highly  probable,  though  of  course  not  quite  certain,  that  any  aconite 
which  does  not  give  this  sensation  of  tingling  and  numbness  to  the 
tongue,  lips  and  pharynx  is  inert,  and  that  the  activity  is  in  direct 
proportion  to  the  amount  or  degree  of  the  sensation  from  a  given  uni- 
form quantity.  Any  bale  of  aconite  root,  every  piece,  or  nearly  every 
piece  of  which  gives  the  tingling  in  some  degree,  must  be  powdered  in 
order  to  get  any  fair  average,  and  therefore  it  is  the  powder  that  must 
be  adopted  as  the  standard.  But  the  powder  is  difficult  to  manage 
and  to  subdivide  properly,  and  so  its  liquid  equivalent,  the  fluid 
extract,  is  much  better.  A  fluid  extract  well  made  by  repercolation, 
and  without  heat,  from  such  root,  so  as  to  represent  the  powder 
in  the  proportion  of  a  minim  to  each  grain,  forms  an  excellent 
standard.  It  has  become  fashionable  of  late  to  add  an  acid  and 
glycerin  to  the  menstruum  in  making  this  fluid  extract,  but  as  they 
are  neither  necessary  nor  useful  they  are  objectionable,  alcohol 
alone  serving  all  the  purposes  of  complete  exhaustion  and  preserva- 
tion of  the  active  principles.  Any  well-made  fluid  extract  of  good 
aconite  root  if  added  to  water  in  the  proportion  of  one  part  to  six 
hundred,  or  one-tenth  of  a  minim  in  a  fluidraehm,  will  give  a  distinct 
aconite  impression  to  the  tongue  and  mouth  under  the  following 
conditions: 
Put  12-5  fluidounces  or  369  cubic  centimeters  of  water  into  a 
proper  vessel  and  add  to  it,  from  an  accurate  pipette,  10  minims  or  '616 
cubic  centimeter  of  the  fluid  extract  of  aconite  root;  stir  well,  and  allow 
it  to  stand  covered  for  an  hour.  This  forms  a  cloudy  solution  or  mix- 
ture from  which,  however,  nothing  settles  out. 
If  now  the  mouth  be  rinsed  out  well  to  free  the  surfaces  from 
mucus  and  saliva,  and  a  fluidraehm  or  3*7  cubic  centimeters  of  this 
solution  be  taken  into  the  anterior  part  of  the  mouth,  and  be  held 
there  in  contact  with  all  the  surfaces  for  one  minute  by  the  watch, 
and  be  then  discharged,  no  immediate  sensation  will  be  felt.  But 
within  fifteen  minutes  a  distinct  aconite  sensation,  not  amountino^ 
to  tingling,  but  very  suggestive  of  it,  will  be  felt  and  will  continue 
for  a  quarter  or  half  an  hour  in  greater  or  less  degree.  The  sensa- 
tion though  distinct,  is  not  pronounced,  and  if  the  attention  was 
