Am'Fe0Ci87h9arm'}  Detection  and  Determination  of  Alcohol,  87 
5.  Iodide  of  starch  solution  will  only  yield  a  reaction  with  concentrated 
solutions. — Ztscbr.f.  Analyt.  Chem.t  1878,  p.  455. 
Determination  of  Hydrocyanic  Acid  in  Bitter  Almond  Water. 
— H.  C.  Vielhaber  uses  Pappenheini's  or  Baedecker's  process,  which 
consists  in  rendering  a  convenient  bulk  of  the  water  slightly  alkaline, 
by  magnesium  hydrate  suspended  in  water,  adding  several  drops  of 
solution  or  potassium  chromate  and  then  carefully  solution  of  nitrate 
of  silver  (1:10),  until  the  red  coloration,  indicating  the  union  of 
chromic  acid  and  oxide  of  silver,  no  longer  disappears.  The  exact 
quantity  of  silver  necessary  for  precipitation  can  thus  be  observed  and 
the  hydrocyanic  acid  be  determined  accurately. — Archiv.  d,  Pharm., 
Nov.,  1878,  p.  408. 
DETECTION  AND  APPROXIMATE  DETERMINATION 
OF  MINUTE  QUANTITIES  OF  ALCOHOL.1 
By  J.  C.  Thresh,  Pharmaceutical  Chemist. 
That  the  detection  of  small  proportions  of  alcohol  is  a  matter  of 
some  importance  is  evident  to  any  one  who  looks  through  the  Year- 
Books  issued  by  our  Conference,  no  less  than  sixteen  papers  bearing 
on  the  problem  being  abstracted  in  the  volumes  already  published.  The 
analyst  desires  a  test  which  will  enable  him  to  detect  with  absolute 
certainty  the  presence  of  alcohol  in  essential  oils  and  other  medica- 
ments when  mixed  therewith,  and  the  physiologist  requires  such  a  test 
to  solve  a  number  of  problems  relating  to  the  action  of  alcohol  upon 
the  system  and  its  presence  or  absence  in  the  tissues  and  animal  fluids. 
Hitherto  no  process  has  been  published  which  is  capable  of  giving  cer- 
tain results  in  such  cases,  either  qualitative  or  quantitative. 
Probably  the  best  test  as  yet  proposed  is  that  of  Lieben  as  modified 
by  Hager  (abs.  Y.  B.  P.,  1871,  237),  which  depends  upon  the  forma- 
tion and  deposition  of  crystals  of  iodoform,  when  solutions  of  iodine 
and  potassium  hydrate  are  added  successively  to  the  warmed  fluid 
containing  alcohol.  This  test  is  said  to  be  capable  of  detecting  1  part 
in  2000  of  water,  but  I  have  failed  to  obtain  by  it  any  decided  reaction 
with  so  dilute  a  solution.  Moreover,  a  number  of  other  volatile  and 
non-volatile  compDunds  yield  the  same  reaction  under  similar  circum- 
1  Read  at  an  Evening  Meeting  of  the  Pharmaceutical  Society  of  Great  Britain, 
Nov.  6,  1878. 
