366  Physiological  Characteristics  of  Acetylene.  {Am(Ug™tr'  SJj™1' 
To  eliminate,  as  far  as  possible,  the  mental  effect  of  the  environ- 
ment, the  subjects  were  engaged  in  playing  a  game  of  cards.  They 
were  interrupted  only  long  enough  to  take  readings  of  their  blood 
pressures,  at  half-hour  intervals.  The  results  of  the  experiment  were 
quite  negative.  The  game  was  continued  throughout  the  period, 
excepting  as  noted.  The  blood  pressure  remained  constant  with 
one  subject  and  was  very  slightly  lowered  from  the  inactivity  with 
two,  and  absolutely  no  effect  was  noted  that  could  be  ascribed  to  any 
poisonous  or  other  action  of  the  acetylene.    It  was  without  effect. 
This  same  result  has  been  obtained  in  experiments  on  animals. 
In  such  amounts  as  used  in  the  above  experiments  there  is  no  effect. 
Indeed,  acetylene  may  be  increased  up  to  20  per  cent,  and,  if  the 
mixture  is  so  made  as  not  to  reduce  the  amount  of  oxygen,  animals 
may  be  left  in  the  atmosphere  for  some  time,  an  hour  or  more,  and 
will  only  become  drowsy,  from  which  they  quickly  recover  when 
removed  into  ordinary  air. 
With  very  large  quantities,  or  with  20  per  cent,  admixtures  act- 
ing for  a  longer  time,  the  degree  of  drowsiness  is  increased.  That 
is  to  say,  the  effect  of  acetylene  in  large  doses  is  that  of  a  narcotic, 
producing  loss  of  consciousness  in  proportion  to  its  degree  of  action. 
When  this  action  is  pushed  to  a  fatal  termination,  the  final  effect  is 
upon  the  breathing  centre,  inhibiting  its  action  and  so  producing 
death. 
It  thus  appears  that  carbide  acetylene  is  not  poisonous  in  the 
sense  that  common  illuminating  gas  is,  and  that  in  large  quantities, 
acting  for  some  time,  it  produces  a  narcotic  action.  In  respect  to 
its  toxicity,  it  presents  no  problem  of  adjustment  under  ordinary 
conditions.  It,  of  course,  may  not  replace  in  large  degree  the  atmos- 
phere we  breathe,  but  otherwise  no  poisonous  action  need  be  antici- 
pated. 
A  number  of  interesting  problems  are  presented  in  connection 
with  the  use  of  the  acetylene  lamp  as  an  illuminant  in  mines.  I  do 
not  refer  to  those  conditions  where  explosive  gases  are  present, 
where  protection  from  explosions  is  obtained  through  the  use  of  the 
Davy  lamp  in  some  of  its  modifications,  but  to  that  large  number 
of  mines  which  are  regularly  illuminated  by  the  naked  flame.  For 
this  purpose,  the  miner's  oil  lamp  has  been  used  for  many  years, 
It  is  light  in  weight,  but  its  illuminating  capacity  is  strikingly  low 
and,  moreover,  is  obtained  at  the  expense  of  a  smoking-out  process 
that  is  amazing.   It  is  a  tribute  to  the  miner's  endurance  that  in  the 
