SUBLIMING  TEMPERATURES  OF  POISONS. 
243 
7.  Strychnine. — Also  yields  ammonia.  (No  mention  of  any 
sublimate.) 
8.  Aconitine. — Evolves  vapors,  first  alkaline,  then  acid. 
These  brief  extracts,  taken  from  a  work  which  is  likely  to 
contain  as  much  information  on  this  subject  as  is  to  be  found  in 
any  one  authority,*  will  serve  to  show  : — 1.  That  two  modes  of 
applying  heat  to  poisonous  matters  are  in  common  use,  and  are 
deemed  to  afford  indications  of  such  value  as  to  serve,  if  not  as 
tests,  at  least  as  necessary  elements  of  their  natural  history ; 
2.  That  these  methods  are  either  so  rough  in  themselves,  or  have 
been  used  for  each  poison  so  rarely  that  some  of  the  phenomena 
to  which  they  give  rise  have  wholly  escaped  observation  ;  and  3. 
That  some  more  delicate  and  precise  mode  of  applying  heat  is 
still  a  great  desideratum. 
Now  it  is  obvious  that  there  would  be  no  difficulty  in  associa- 
ting with  these  rough  methods  the  determination  of  the  temper- 
ature at  which  the  several  poisons  melt  or  sublime,  and  equally 
obvious  that  out  of  such  association  there  must  inevitably  arise 
such  striking  differences  and  contrasts  as  would  serve  the  pur- 
poses both  of  accurate  physical  history  and  of  diagnosis.  It 
would  suffice  to  plunge  the  bulb  of  a  thermometer  indicating  high 
temperatures,  and  a  short  reduction-tube  made  of  glass  of  the 
same  thickness  as  the  tube  of  the  thermometer  itself,  side  by 
side  into  melting  oil,  a  sand-bath,  or  even  a  hollow  nipple  of 
copper  or  brass.  The  melting  and  subliming  temperatures  would 
thus  be  ascertained  under  the  necessary  conditions  of  equality 
of  heat,  and  the  sublimates  would  form  in  the  higher  part  of  the 
tube.  If  the  tube  were  made  of  the  glass  which  presents  in  sec- 
tion a  flattened  ellipse,  and  it  were  drawn  out  into  a  capillary 
tube,  it  would  be  easy  to  seal  the  capillary  portion  at  both  ends, 
and  examine  the  contents  under  the  microscope. 
But  as,  by  adopting  this  plan,  we  should  sacrifice  the  great 
advantages  which  obviously  arise  from  substituting  a  flat  surface 
of  glass  for  the  reduction-tube,  I  did  not  hesitate  to  prefer  an 
arrangement  which  would  enable  me  to  ascertain  the  melting  or 
subliming  temperature,  or  both,  with  sufficient  accuracy  for  every 
*  "The  Principles  and  Practice  of  Medical  Jurisprudence,"  by  Alfred 
Swaine  Taylor,  M.D.,  F.R.S.,  etc. 
