490  Standardisation  of  Aconite  Preparations.  {A^virerPi9iT' 
animals  should  always  be  of  the  same  species,  and  care  must  be  taken 
to  have  all  conditions  the  same  in  different  assays. 
The  preparation  to  be  tested  is  reduced  in  its  alcoholic  content 
and  the  calculated  dose  injected  into  the  ventral  lymph-sac.  The 
animals  are  observed  at  the  end  of  twenty-four  hours  and  note  made 
as  to  those  that  survive  and  those  that  succumb. 
In  the  guinea-pig  method,  as  used  by  Roth,  the  dose  is  calculated 
per  gramme  body  weight  and  the  solution,  reduced  in  its  alcoholic 
content,  is  injected  beneath  the  skin  of  the  abdomen.2  In  Hatcher's 
method,  cats  are  used,  and  the  properly  diluted  and  isotonic  solution 
is  injected  intravenously  over  an  extended  period  of  time  until  the 
death  of  the  animal  occurs.  The  method  is  essentially  the  same  as 
the  cat  method  for  the  assay  of  the  digitalis  bodies. 
Roth's  paper  2  contains  a  report  of  his  studies  on  the  various 
physiological  methods,  with  the  exception  of  Hatcher's.  We  have 
recently  carried  out  tests  on  five  commercial  samples  of  tincture  of 
aconite  with  a  view  of  gaining  information  on  the  following  points: 
1.  The  agreement  in  the  results  secured  by  the  different  physi- 
ological methods. 
2.  The  quality  of  aconite  on  the  local  market. 
The  second  point  is  of  particular  importance  in  Richmond,  on 
account  of  the  rather  extensive  employment  of  aconite  in  spite  of  its 
questionable  therapeutic  value.  The  features  of  the  investigation 
bearing  on  this  point  have  been  published  in  another  paper,4  and  we 
shall  here  confine  ourselves  to  a  discussion  of  the  methods  of  assay 
used. 
Of  the. five  samples  used  in  our  investigation,  three  were  per- 
colated by  the  local  pharmacists  from  drugs  that  they  had  purchased  ; 
the  other  two  were  manufactured  by  two  of  the  large  manufacturers. 
Of  the  latter  two  samples,  one  was  supposed  to  have  been  tested 
physiologically,  the  other  by  the  chemical  method. 
There  are,  on  theoretical  grounds,  several  objections  to  the  taste 
method.  It  would  seem  that  the  susceptibility  of  the  individual  ob- 
server is  apt  to  vary  considerably ;  that  imagination  plays  an  im- 
portant role  in  producing  the  aconite  "  impression  " ;  and  there  is  the 
added  objection  that  there  is  no  definite  record  made,  such  as  the 
graphic  record  secured  in  the  blood-pressure  method  in  testing 
adrenalin.  Consequently,  we  undertook  tests  with  this  method  in  a 
somewhat  prejudiced  frame  of  mind,  which  may  partly  account  for 
the  unsatisfactory  results.    However  that  may  be,  in  our  hands  the 
