io8 
The  Detection  of  Methyl  Alcohol. 
(Am.  Jour.  Ffaarm. 
X      March,  1905. 
and  so  we  cannot  depend  absolutely  upon  the  result  of  the  reducing 
test. 
In  1899,  Mulliken  and  Scudder  published  a  method  (Am.  Client. 
Jour.,  21,  page  266),  whereby  a  mixture  of  methyl  and  ethyl  alcohol 
is  oxidized  in  solution  by  the  action  of  heated  metallic  copper,  pro- 
ducing the  corresponding  aldehydes.  Any  formaldehyde  so  obtained 
is  then  recognized  by  characteristic  color  tests. 
This  method,  in  a  somewhat  modified  and  improved  form,  -was 
brought  out  later  by  Dr.  A.  B.  Prescott  and  by  Leonard  D.  Haigh. 
(Pharmaceutical  Review  of  October,  1903.) 
In  the  form  in  which  Dr.  Prescott  communicated  it  to  the  U.  S. 
Pharmacopoeia  Revision  Committee,  it  was  as  follows : 
Test  for  Methyl  Alcohol. — In  a  test-tube  of  the  capacity  of  about 
40  cm.,  take  of  the  alcohol  or  spirit  to  be  tested,  if  it  be  undiluted, 
1  c.c.  and  add  distilled  water  to  make  10  c.c.  in  all.  If  the 
alcohol  be  judged  to  be  already  dilute  take  a  correspondingly  larger 
measure  of  it  and  dilute  this  to  10  c.c,  so  that  the  proportion  of 
the  alcohol  shall  not  be  more  than  10  per  cent,  by  volume  in  the 
liquid.  A  copper  wire  spiral  (test  reagent)  is  to  be  heated  to  red- 
ness in  a  flame  free  from  soot,  then  plunged  steadily  quite  to  the 
bottom  of  the  liquid  in  the  test-tube  and  held  there  for  a  second  or 
two,  then  withdrawn  and  dipped  in  water  to  cool.  This  treatment 
with  red  hot  copper  is  to  be  repeated  five  or  six  times,  immersing 
the  test-tube  in  cold  water  to  keep  down  the  temperature  of  the 
liquid.  The  contents  of  the  test-tube  are  now  filtered  into  a  wide 
test-tube  and  boiled  very  gently  over  the  flame.  If  there  be  odor 
of  acetaldehyde  perceptible  the  boiling  is  to  be  continued  until 
this  odor  nearly  or  quite  ceases  to  be  clearly  distinguished.  The 
liquid  is  now  cooled,  poured  into  a  white  porcelain  dish  with  con- 
cave bottom,  and  lastly  treated  with  the  addition  of  five  drops  (or 
1  c.c.)  of  phloroglucinol  alkali  solution  (test  reagent). 
The  color,  if  any,  caused  by  the  reagent  should  not  be  deeper 
than  pale  yellowish  red,  and  should  fade  rapidly  away. 
(A  deep  red  color  persisting  two  or  three  minutes  and  longer,  the 
reaction  of  formaldehyde,  indicates  methyl  alcohol  taken  for  the 
test.  A  pale  or  slight  yellowish  red  color  fading  rapidly,  the  reac- 
tion of  acetaldehyde,  results  when  only  ethyl  alcohol  is  taken,  the 
acetaldehyde  produced  by  the  treatment  not  being  wholly  driven 
off  by  the  gentle  boiling.) 
