542 
SUBLIMATION  OF  THE  ALKALOIDS. 
dilution  and  drop-measurement,  goes  far  to  answer  this  ques- 
tion ;  but  I  sought  a  more  complete  answer  by  dealing  with  a 
small  and  thin  deposit  from  a  solution  of  strychnine  in  benzole, 
which  deposit  did  not  present  any  definite  crystals  when  exam- 
ined by  the  microscope.  Comparing  it  with  the  sublimates  on 
which  I  had  just  been  experimenting,  I  should  estimate  its 
weight  as  not  exceeding  the  fifteen-hundredth  part  of  a  grain. 
This  spot  gave  four  successive  sublimates  having  the  crystalline 
form  of  strychnine. 
In  both  these  cases,  whether  operating  with  the  sublimate  or 
with  the  deposit  from  solution  in  benzole,  the  procedure  was 
perfectly  simple,  and  the  result  apparently  certain.  The  alka- 
loid does  not  melt,  but  sublimes  as  a  deposit  of  arsenious  acid 
from  a  solution  in  water  does.-  The  flame  of  the  spirit-lamp  was 
continuously  applied  to  the  glass  disk,  a  shallow  glass  cell  with 
wide  opening  was  superimposed  so  as  to  surround  the  spot,  and 
the  sublimate  was  received  on  a  second  glass  disk,  carefully 
cleaned  and  dried  by  being  passed  through  the  flame  of  the 
lamp. 
There  are  other  preliminary  questions  not  raised  in  Helwig's 
work,  but  which  are  too  important  to  be  overlooked.  Is  subli- 
mation a  property  of  the  alkaloids  and  the  allied  active  princi- 
ples as  a  class  ?  is  one  of  these.  I  sought  for  an  answer  to  this 
question  by  preliminary  experiments  with  thirty-seven  sub- 
stances, in  which  were  comprised  all  the  active  poisons  and  medi- 
cines ;  and  I  found  that,  at  the  first  experiment,  no  less  than 
fifteen  out  of  the  thirty-seven  gave  distinct  crystalline  sublimates. 
So  that  it  may  be  safely  asserted  that  upwards  of  one-third  of 
these  substances  respond  to  the  test  of  sublimation.  The  re- 
mainder, after  melting,  like  the  rest,  (cantharidine  excepted, 
which  sublimes  without  melting)  gave  off  vapor  which  was  depo- 
sited on  the  glass  disk  as  watery  patterns,  generally  mixed  with 
crystalloids.  Now,  as  even  those  alkaloids  which  ordinarily 
yield  crystalline  sublimates  do  exceptionally  furnish  these  wa- 
tery patterns,  it  is  not  improbable  that  the  list  of  substances 
giving  sublimates  of  more  defined  form  would  be  extended  by 
repeating  the  experiments  with  them,  and  learning  by  practice 
the  temperature  which  suits  them  best.    Indeed,  I  have  already 
