AMYLENB. 
241 
tion.  He  gives  the  following  quotation  from  Sir  Humphrey 
Davy's  Researches  concerning  Nitrous  Oxide,  published  in  the 
first  year  of  this  century :  « As  nitrous  oxide  in  its  extensive 
operation  seems  capable  of  destroying  physical  pain,  it  may  pro- 
bably be  used  with  advantage  during  surgical  operations  in  which 
no  great  effusion  of  blood  takes  place."  About  forty  years  after 
the  publication  of  this  sentence  nitrous  oxide  was  used  with 
doubtful  success  by  Mr.  Wells,  a  dentist,  of  Hartford,  Connecti- 
cut, in  some  cases  of  tooth  extraction  :  but  its  use  was  speedily 
relinquished,  the  effect  being  considered  uncertain.  In  Sep- 
tember, 1846,  Br.  Morton,  who  had  previously  been  in  partner- 
ship with  Mr.  Wells,  and  had  witnessed  the  trials  with  nitrous 
oxide,  administered  the  vapor  of  sulphuric  ether  with  success  in 
a  case  of  tooth  drawing,  and  afterwards  in  surgical  operations. 
This  led  to  the  general  use  of  ether  vapor.  In  1847  Mr.  Jacob 
Bell  substituted  the  substance  known  as  chloric  ether  for  sul- 
phuric ether,  and  this,  although  not  sufficiently  active,  was  found 
to  produce  insensibility.  In  the  autumn  of  1847  Mr.  Waldie, 
of  Liverpool,  being  in  Edinburgh,  explained  to  Dr.  Simpson  that 
the  so-called  chloric  ether  was  a  solution  of  chloroform  in  spirit, 
whereupon  the  latter  obtained  some  pure  chloroform  and  ad- 
ministered it  with  great  success.  Dr.  Snow  states,  "  Ever  since 
the  introduction  of  chloroform  I  have  been  of  opinion  that  other 
agents  would  be  met  with  more  eligible  for  causing  anaesthesia 
by  inhalation.  It  seemed  improbable  that  this  one,  which 
happened  to  be  standing  on  the  shelf  of  the  Pharmaceutical 
Chemist  for  another  purpose,  should  be  better  than  all  the  very 
numerous  volatile  compounds  which  organic  chemistry  is  daily 
bringing  to  light ;  and  the  continued  use  of  chloroform  is  probably 
due  to  the  circumstance,  that  hardly  any  one  has  made  anaesthesia 
by  inhalation  a  subject  of  constant  and  protracted  investigation. 
I  have  from  time  to  time  made  experiments  on  animals  with  a 
variety  of  substances,  and  I  find  that  the  agents  which  might  be 
inhaled  for  the  prevention  of  pain,  in  the  absence  of  others  which 
are  more  eligible,  are  extremely  numerous.  They  include,  among 
other  things,  carbonic  acid  and  carbonic  oxide  gases,  olefiantgas, 
the  vapor  of  hydrocyanic  acid,  and  cyanogen  gas  ;  which  last  is 
contained,  as  I  found,  in  the  fumes  of  the  puff-ball,  which  Dr. 
Richardson  brought  before  the  notice  of  this  Society.  The 
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