SUBLIMATION  OF  THE  ALKALOIDS.  543 
found  that  by  multiplying  experiments  with  the  members  of  the 
opium  group,  I  have  transferred  three  of  them  (papaverine,  nar- 
ceine,  and  paramorphine)  from  my  list  of  alkaloids  not  yielding 
crystalline  sublimates  to  that  of  alkaloids  which  afford  such  sub- 
limates, at  least  occasionally.  If  to  the  alkaloids  which  give 
characteristic  sublimates  we  were  to  add  those  which,  though 
not  characteristic  in  form,  give  peculiar  reactions,  we  should 
probably  find  that  more  than  half  of  all  these  substances  are  rec- 
ognizable through  the  form  of  their  sublimates,  or  through  their 
reactions  with  liquid  tests.  Sublimation,  then,  may  be  safely 
added  to  the  list  of  those  properties  of  the  alkaloids  which  go  to 
make  up  a  complete  description. 
But  it  may  be  asked  : — Is  this  property  of  sublimation  by  heat 
and  deposit  on  cooler  surfaces  the  exclusive  possession  of  a  small 
group  of  metallic  poisons  (such  as  arsenious  acid,  calomel,  and 
corrosive  sublimate)  and  the  alkaloids  and  analagous  active  prin- 
ciples ?  We  already  know  that  an  animal  product,  cantharidine, 
sublimes  unchanged,  and  deposits  itself  in  very  distinct  crystal- 
line forms  ;  and  that  camphor  sublimes  at  common  temperatures, 
and  settles  on  glass  bottles  and  shades  in  beautiful  octahedral 
crystals ;  and  I  may  add,  as  a  sufficient  present  answer  to  the 
question,  that  I  obtain  crystalline  or  other  well-marked  deposits 
from  urea,  uric  acid,  hippuric  acid,  alloxan,  and  uramile  ;  and 
from  benzoic,  tannic,  iodic,  and  tartaric  acids,  these  being  sub- 
stances which  I  happen  to  have  at  hand. 
It  may,  therefore,  be  safely  affirmed  that  sublimation  and  de- 
posit on  cooler  surfaces  (often  in  forms  eminently  characteristic, 
and  with  changes  of  form  and  color  not  less  striking)  are  proper- 
ties not  only  of  arsenious  acid,  corrosive  sublimate,  and  a  small 
group  of  inorganic  substances  to  which  it  was  first  applied,  and 
for  which  I  devised  the  simple  procedure  already  described,  but 
also  of  a  vast  number  of  organic  products,  among  which  the  al- 
kaloids and  active  principles  constitute  only  one  class, 
There  is  still  one  more  preliminary  question,  to  which  Dr. 
Helwig  does  not  refer,  but  which  is  both  interesting  and  impor- 
tant ;  namely,  do  the  salts  of  the  alkalies  yield  sublimates  as 
well  as  the  alkaloids  themselves  ?  An  answer  to  this  question, 
sufficient  for  my  present  purpose,  is  furnished  by  the  statement 
