*  EMPLOYMENT  OF  MEDICINAL  HYDROCYANIC  ACID.  345 
cho-Quinine  "  point  conclusively  to  the  absence  of  quinia,  quini- 
dia  and  cinchonidia  in  the  sample  under  examination,  and  we 
can  safely  assert  that  "  Cincho-Quinine  "  is  in  reality  only  cin- 
chonia  containing  about  two  per  cent,  of  quinicia  and  cinchonicia. 
In  reviewing  the  above  experiments  and  results  in  connection 
with  Jas.  R.  Nichols  &  Co.'s  circular,  we  unhesitatingly  arrive 
at  the  following  conclusions  : 
"  Cincho-Quinine,"  although  having  the  advantage  of  being 
nearly  tasteless,  does  not  contain  quinia,  quinidia  and  cinchonidia, 
and  therefore  does  not  represent  the  whole  of  the  active  princi- 
ples of  the  bark. 
It  cannot  exert  the  full  effects  of  sulphate  of  quinia  in  the 
same  dose,  inasmuch  as  the  stated  dose  of  "  Cincho-Quinine  "  is 
from  five  to  thirty  grains. 
Although  ^' Cincho-Quinine  "  appears  to  cost  less  than  sul- 
phate of  quinia,  it  does  not  follow  that  commercial  "  Cinchonia," 
sold  at  four  times  its  value,  is  a  desirable  substitute  for  quinine 
in  an  economical  point  of  view. 
And,  lastly,  one  very  important  principle  should  by  no  means 
be  lost  sight  of,  namely  :  that  a  physician  should  always  know 
what  he  is  prescribing,  and  therefore  the  substitution  of  a  remedy 
of  less  eflBciency  and  uncertain  medicinal  value,  is  altogether  un- 
warrantable and  often  hazardous. — Pasifio  Med.  and  Surg, 
Journ.^  Aprils  1870. 
ON  THE  EMPLOYMENT  OF  MEDICINAL  HYDROCYANIC 
ACID. 
By  M.  Donovan,  M.R.I.A. 
In  prescribing  hydrocyanic  acid  medical  practitioners  occa- 
sionally indicate  what  they  believe  to  be  a  specific  strength  by 
directing  "  Scheele's  acid"  to  be  used  in  compounding  their  pre- 
scriptions. The  practical  effect  is  to  cause  some  degree  of  doubt 
in  the  mind  of  the  compounder,  bound,  as  he  is,  to  the  provisions 
of  the  Pharmacopoeia,  on  the  one  hand,  and  the  instruction  given 
by  the  prescriber,  on  the  other. 
In  some  establishments  two  denominations  are  to  be  found — 
one  prepared  according  to  B.  P.,  the  other  according  to  the  pre- 
vailing opinion  that  Scheele's  acid  should  be  of  three-fold 
