TUKPENTINE  AN  ANTIDOTE  TO  PHOSPHORUS. 
175 
A  single  drop  of  a  solution  of  hydrocyanic  acid  containing  1 
per  cent,  of  real  acid,  is  placed  in  a  vase  of  20  litres  capacity. 
A  strip  of  the  prepared  paper  is  suspended  by  a  wire  in  the 
middle  of  the  vase,  which  is  then  covered.  The  blue  tint  rapidly 
becomes  apparent.  A  drop  measures  <2ot\i  of  a  cubic  centimetre, 
and  the  vase  holds  20  litres,  or  20,000  cubic  centimetres ;  con- 
sequently, the  relation  of  the  drop  to  the  vase  is  1  to  20  times 
20,000,  or  1  to  400,000.  But  the  drop  contains  only  1  per 
cent,  of  real  acid,  therefore  the  proportion  of  hydrocyanic  acid 
in  the  vase  is  1  in  400,000  +  100,  or  1  in  40,000,000.  The 
author  states  that  this  division  may  be  pushed  even  further,  and 
thatl  in  120,000,000  of  air  may  be  detected. 
The  following  experiment  indicates  the  value  of  this  test  in 
toxicological  inquiries: — A  piece  of  fresh  meat,  weighing  600 
grammes,  was  divided  into  two  equal  parts ;  one  part  was 
sprinkled  with  20  drops  of  the  1  per  cent,  solution  of  hydro- 
cyanic acid,  and  then  exposed  to  the  air  for  twenty-four  hours. 
At  the  and  of  this  time  it  was  placed  in  a  vase  of  25  litres  capa- 
city, and  a  piece  of  the  test  paper  suspended  over  it.  In  two 
minutes  the  coloration  of  the  paper  commenced,  and  a  few 
minutes  later  was  complete.  The  other  piece  of  meat  was  kept 
for  comparison,  and  exposed  in  another  vase  in  precisely  the 
same  manner,  but  no  reaction  was  obtained.  Careful  experi- 
ments were  made  with  this  paper  upon  the  vapors  of  other  acids, 
but  these  exerted  no  influence.  The  color  developed  on  the 
paper  by  hydrocyanic  acid  remains  for  a  long  time,  but  dimin- 
ishes as  the  paper  dries.  After  several  days  it  passes  to  a 
greenish-grey,  but  revives  slightly  on  remoistening  the  paper.— 
Lond.  Pharm.  Journ.^  Jan.,  1860. 
TURPENTINE  AN  ANTIDOTE  TO  PHOSPHORUS. 
M.  Vigla  states  that,  in  a  certain  lucifer  factory,  the  work- 
men who  dip  the  matches  wear  on  their  chest  a  little  vessel 
containing  essence  of  turpentine,  which  is  said  to  preserve  the 
operators  from  the  evil  effects  of  the  phosphorous  vapors.  It  is 
well  known  that  the  vapor  of  turpentine,  and  many  other  hydro- 
carbons completely  extinguishes  the  phosphorescent  light  which 
