150  The  Metameric  Amyl  Nitrites.  {A™u™&Vimm 
96°-97°  C.  and  was  dextrorotatory.  The  lsevorotatory  /3-amyl  alcohol 
had  given  rise  to  a  dextrorotatory  nitrite.  Le  Bel  (Bull  Soc.  [2], 
xxv.,  545)  has  shown  that  the  amyl  chloride,  bromide  and  iodide 
prepared  from  the  lsevorotatory  alcohol  are  also  dextrorotatory. 
The  physiological  action  of  the  mixture  of  a-amyl  and  /9-amyl  ni- 
trites thus  prepared  has  been  investigated  by  Professor  Cash,  who 
finds  that  it  produces  in  animals  a  rapid  fall  of  blood  pressure,  an  ac- 
celeration of  the  pulse-rate,  and  a  slowing  of  the  respiratory  move- 
ments, although  it  does  not  appear  to  act  so  powerfully  in  these  re- 
spects as  iso-butyl  nitrite. 
In  order  to  separate  these  two  metameric  nitrites,  it  was  necessary 
first  to  obtain  the  corresponding  alcohols.  The  separation  of  the  two 
alcohols  was  first  effected  by  Pasteur  (Compt.  Rend.,  xli.,  296),  by 
converting  them  into  two  barium  amyl-sulphates,  and  repeatedly  recrys- 
talli zing  these  salts  from  water,  by  which  means  it  is  possible  to  obtain 
the  pure  salt  corresponding  to  the  inactive  alcohol,  and  after  several 
further  series  of  recrystallizations  of  the  residual  salts,  that  corres- 
ponding to  the  active  alcohol ;  the  barium  salt  of  /3-amyl-sulphuric 
acid  being  about  two  and  a  half  times  more  soluble  than  the  barium 
salt  of  a-amyl-sulphuric  acid.  This  process  of  isolation  is  very  la- 
borious, and  has  not  often  been  repeated ;  in  fact,  it  is  doubtful 
whether  the  active  alcohol  has  yet  been  obtained  pure,  since  specimens 
prepared  by  different  observers  have  not  exhibited  the  same  rotatory 
power.  Le  Bel  has  proposed  to  separate  the  two  alcohols  by  the  pro- 
longed action  of  gaseous  hydrochloric  acid,  when  the  inactive  alcohol 
is  more  readily  attacked  and  converted  into  the  chloride,  than  the  ac- 
tive alcohol.  It  seems  however  from  the  experience  of  other  ob- 
servers that  this  method  is  hardly  less  tedious  than  Pasteur's,  and  as 
the  latter  method  had  already  been  successfully  employed  by  Pedler, 
we  decided  to  attempt  to  effect  the  separation  by  its  means. 
Fusel  oil,  which  had  been  distilled  with  steam,  was  dried  and  frac- 
tionated. The  fraction  obtained  between  127°-132°,  after  having 
been  several  times  redistilled,  exercised  a  rotation  of  -1°  (for  the  D 
ray),  in  a  tube  200  mm.  long,  at  15°  C,  the  determination  being  made 
in  Laurent's  instrument.  If  we  take  — 8*8°  (Ley)  as  the  rotatory 
power  of  the  active  alcohol  under  the  same  conditions,  then  this  liquid 
was  constituted  of  88*64  per  cent,  of  a-amyl  alcohol  and  11*36  per 
cent,  of  £-amyl  alcohol.  Aboul  1 J  litre  was  warmed  for  one  week 
with  an  equal  weight  of  sulphuric  acid,  the  mixture  was  largely  di- 
