248 
SUBLIMING  TEMPERATURES  OF  POISONS. 
Codeia  melts  at  or  about  220°  sublimes  at  or  about  220° 
Narcotina      "  "       240°       "  "  310° 
Crjptopia      "  "       350°        "  "  350° 
All  these  substances,  it  need  not  be  stated,  yield,  like  morphia 
and  strychnia,  a  more  or  less  abundant  carbonaceous  residue, 
by  which  the  alkaloids  and  glucosides  are  distinguished  from 
most  other  bodies.  To  these  distinctive  characters  that  of  giving 
out  a  marked  odor,  in  some  cases  agreeable,  in  others  offensive, 
ought  to  be  added.  As  the  result  of  repeated  careful  experi- 
ments, both  with  platinum-foil  and  the  porcelain  slab,  I  give  the 
following  : — Strychnia,  pleasant  but  not  easy  to  describe  ;  mor- 
phia and  atropia,  as  of  singeing  ;  brucia,  as  of  burnt  horn  ; 
aconitia,  not  disagreeable,  but  ill-defined ;  veratria,  mousy  and 
irritating  to  the  nostrils  ;  digitalina,  as  of  the  drug  ;  solania, 
as  of  roast  apple. 
On  comparing  class  2  with  class  3,  it  will  be  obvious  that, 
with  common  care  in  applying  heat,  it  would  not  be  possible  to 
confound  the  two  important  alkaloids,  morphia  and  strychnia, 
with  any  other  known  poisons.  A  white  powder  or  crushed  crys- 
tal, which  first  sublimed  at  330°,  or  from  that  to  345°,  melted  at 
some  higher  temperature,  and  continued  to  yield  sublimates  till 
it  left  a  final  carbonaceous  deposit,  must  be  either  morphia  or 
strychnia.  If  both  changes  happened  at  the  lower  tempera- 
tures indicated  in  the  table,  it  would  be  morphia ;  if  at  the 
higher,  strychnia.  The  peculiar  white  disks  developed  in  the 
sublimate  are  common  to  the  two  alkaloids,  and  the  forms  of  the 
sublimates  might  also  not  prove  characteristic.  Hence  it  might 
be  necessary  to  resort  to  the  color  test  or  the  carbazotic-acid 
test,  to  render  the  diagnosis  certain.  A  glance  at  the  tables 
will  show  that  many  of  the  alkaloids  or  glucosides  melt  and  sub- 
lime also  at  temperatures  so  low  as  not  to  admit  of  being  con- 
founded with  either  of  these  important  poisons. 
It  will  be  observed  that  some  of  the  poisons  in  class  3  (digita- 
lina, picrotoxia,  and  solania,  in  the  first  group,  and  codeia  and 
cryptopia,  in  the  second)  have  appeared  to  melt  and  sublime  at 
the  same  temperature.  They  have  seemed  to  melt  and  then  sub- 
lime, with  a  scarcely  appreciable  interval.  As  there  is  not  ap- 
parently even  the  small  difference  of  10°  shown  in  the  case  of 
