198 
Methylal. 
( Am.  Jour.  Pharm. 
X      April,  1887. 
Bitter,  however,  after  carefully  excluding  all  possibility  of  any  entrance 
of  the  fluids  into  the  system  through  the  mouth  or  respiratory  pas- 
sages, was  utterly  unable  to  find  in  the  urine  the  slightest  trace  of  the 
salicylate  of  soda  or  iodide  of  potassium  with  which  he  experimented, 
and  therefore  confirms  the  result  of  former  experiments  of  his,  that 
the  normal  skin  is  not  permeable  to  substances  in  spray-solutions. — 
Med.  Chronicle,  Febr.,  1887;  Berlin.  Klin.  Woehensehrift. 
METHYLAL.* 
By  B.  W.  Richardson,  M.  I).,  F.  R.  S. 
At  a  meeting  of  the  British  Association  for  the  Advancement  of 
Science,  held  at  Norwich,  in  1868,  I  brought  out  for  the  first  time  the 
chemical  fluid  called  Methylal  as  an  anaesthetic  and  hypnotic,  and  at  a 
meeting  of  the  same  Association  at  Exeter,  in  1869,  I  again  drew  at- 
tention to  it  in  order  to  make  it  useful  in  practice.f 
Methylal  is  a  colorless  fluid  of  specific  gravity  0*855;  its  vapor 
density  is  38°,  taking  hydrogen  as  unity ;  and  boiling-point  of  42° 
Cent.,  107*6°  Fahr.  Its  solubility  in  blood  is  one  part  in  three  ;  its 
composition  is  C3H802.  It  is  made  by  distilling  methylic  alcohol  with 
sulphuric  acid  in  the  presence  of  peroxide  of  manganese,  but  it  requires 
several  re-distillations  before  it  can  be  obtained  in  the  pure  state,  for 
which  reason  it  is  at  present  a  very  expensive  compound.  The  first 
specimens  with  which  I  experimented  were  made  in  my  own  lab- 
oratory ;  later  specimens  have  been  made  for  me,  with  much  care,  by 
my  friend  Mr.  Williams,  the  well-known  operative  chemist. 
When  methylal  is  quite  pure  it  is  almost  tasteless,  but  bites  the 
tongue,  and  owing  to  its  low  boiling-point  quickly  evaporates.  The 
odor  of  it  is  fragrant,  and  not  very  powerful.  The  pure  vapor  creates 
no  irritation  on  being  breathed. 
After  long  exposure  to  the  vapor  of  methylal,  in  an  atmosphere 
containing  not  less  than  35  per  cent,  of  the  vapor,  warm-blooded  ani- 
mals may  be  made  to  pass  into  a  sleep  which,  once  established,  is  deep 
and  prolonged.  In  my  first  researches  the  sleep  so  induced  lasted  for 
intervals  of  two  and  even  three  hours,  but  I  believe  now  that  this  long 
narcotism  was  due  to  the  presence  of  acetone,  from  the  methylal  not 
*From  the  Asclepiad  No.  13.  Reprinted  from  Phar.  Jour,  and  Trans.,  Feb. 
13,  1887. 
f  '  Reports  of  the  British  Association  for  the  Advancement  of  Science.'  vol 
xxviii.,  pp.  183-4,  Norwich  meeting ;  and  vol.  xxix.  p.  406,  Exeter  meeting. 
