SUBLIMATION  OF  THE  ALKALOIDS. 
511 
using  such  quantities  as  the  thousandth  of  a  grain.  Now,  as  it 
is  quite  obvious  that  in  order  to  prove  the  utility  of  the  method 
of  sublimation  we  must  begin  by  demonstrating  its  delicacy,  I  lost 
no  time  in  ascertaining  this  point  for  myself  by  operating  with 
the  alkaloid  strychnine.  I  had  the  one-hundredth  of  a  grain  of 
this  substance  weighed  in  a  delicate  balance,  and,  with  common 
care,  obtained  fourteen  successive  sublimates,  eleven  before  the 
change  of  color  or  melting  of  the  alkaloid,  and  three  afterwards. 
As  the  fifteenth  sublimate  was  smoky,  it  was  not  reckoned,  and 
the  process  was  not  carried  further.  Of  these  fourteen  subli- 
mates, eight  showed  crystalline  forms  under  the  microscope,  and 
the  rest  were  distinct  and  granular.  Of  this  latter  class  I  se- 
lected one,  which  certainly  could  not  have  weighed  the  fifteen- 
hundredth  of  a  grain,  and,  having  taken  extreme  precautions  to 
ensure  the  absence  of  any  trace  of  strychnine  except  in  the 
crust,  obtained  from  it  two  well-marked  sublimates,  showing 
beautiful  crystalline  forms  under  the  microscope,  a  third  dis- 
tinctly granular,  and  reacting  most  characteristically  with  one 
of  the  liquid  reagents,  and  a  fourth  and  fifth  quite  distinct,  but 
neither  crystalline  nor  granular.  The  glass  from  which  the  sub- 
limates had  been  driven  oif  retained  a  visible  stain.  If,  then, 
we  reject  the  last  two  crusts,  we  still  have  a  sublimate  consist- 
ing of  grain,  yielding  three  characteristic  deposits.  So  that 
a  quantity  as  small  as  ^  grain  would  yield  abundant  evidence 
of  the  presence  of  strychnine.  I  repeated  this  experiment  with 
another  smaller  crust  of  the  same  series  of  fourteen,  and  obtained 
two  well-marked  crystalline  sublimates.  So  that  1  am  able  to 
state  that  a  crust  not  weighing  more  than  the  fifteen-hundredth 
of  a  grain  will  yield  other  crusts,  two  or  three  in  number,  hav- 
ing the  unmistakable  characters  of  strychnine  sublimates,  and 
one  or  other  of  which  must  weigh  as  little  as  from  the  three- 
thousandth  to  the  five-thousandth  part  of  a  grain. 
Out  of  this  conclusive  experiment  arose  a  question  of  great 
interest :  Could  such  sublimates  be  obtained  from  small  quanti- 
ties of  strychnine  deposited  from  solutions  of  the  alkaloid — from 
such  solutions  as  would  be  formed  in  the  course  of  medico-legal 
investigations  ?  The  fact  stated  above,  that  Dr.  Helwig  ascer- 
tained the  quantities  of  the  alkaloid  submitted  to  sublimation  by 
