AFeb0Ui;  i874RM'}    Examination  of  Hydrocyanic  Acid.  71 
moval  from  a  40  oz.  bottle,  which  has  been  in  stock  several  months, 
during  which  time,  however,  the  stopper  had  not  been  withdrawn." 
"  Both  samples  have  been  carefully  preserved  in  bottles  encased  in 
blue  paper,  and  kept  in  a  cupboard  in  a  cool  underground  cellar." 
Nos.  2,  7,  8,  and  9  were  portions  of  the  contents  of  dispensing 
bottles  kindly  given  me  by  friends  who  share  with  us  the  desire  for  a 
more  perfect  preparation. 
Of  the  three  samples  of  "  Scheele's  acid," 
No.  10  had  been  in  stock  for  several  months,  during  which  time  the 
stopper  had  been  frequently  removed. 
No.  11  was  a  fresh  sample,  obtained  expressly  for  examination, 
and 
No.  12  was  an  acid  of  unknown  birth.  Its  owner  regarded  it  as  a 
curiosity,  and,  like  most  curiosities,  it  is  only  fit  to  be  kept  on  a  shelf. 
Here,  then,  gentlemen,  are  nine  samples  of  hydrocyanic  acid,  B.P., 
taken  from  various  sources,  and  representing  very  fairly,  I  should 
say,  the  condition  in  which  this  medicine  is  generally  met  with. 
It  will  be  seen  at  a  glance  that  no  two  samples  are  alike,  and  all, 
with  one  exception,  considerably  below  the  standard.  That  such 
should  be  the  case  must  be  regarded  as  a  matter  of  grave  importance  ; 
and  the  question  so  frequently  asked  before  I  ask  once  again — Can 
this  variation  in  so  important  a  remedy  be  obviated  ?  There  is  no 
doubt  it  arises  chiefly  from  the  extreme  volatility  of  the  substance 
itself.  This  was  brought  home  to  us  most  convincingly  during  the 
conduct  of  our  experiments.  HCy  is  much  more  volatile  than  water, 
hence  the  slightest  exposure  does  something  to  weaken  the  sample. 
I  feel  bound  therefore  to  answer  that  I  fear  nothing  can  entirely  pre- 
vent this  unfortunate  variation  in  commercial  hydrocyanic  acid.  But 
I  think  at  the  same  time  that  more  may  be  done  than  is  always  done 
to  limit  this  variation,  and  I  hazard  the  opinion  that  a  difference  so 
great  as  that  here  shown  ought  not  to  exist  in  any  neighborhood. 
In  the  management  of  this  chemical  it  is  of  the  utmost  importance 
that  every  chemist  should  test  for  himself  the  strength  of  his  solution  ; 
without  so  doing  he  can  know  absolutely  nothing  of  the  real  strength 
of  the  article  sent  him.  But  starting  with  an  acid  of  full  strength 
and  keeping  it  under  the  most  favorable  circumstances,  he  may  then 
have  fair  reason  to  expect  success  in  his  endeavors  to  render  this 
powerful  agent  something  like  a  reliable  remedy  in  the  hands  of  the 
medical  man. 
