'OInT  i^IiE  SUBLlMAlIOft  Oft  tHE  ALKALOIDS. 
435 
Vhen  only  a  few  experiments  are  intended  to  be  made.*  An 
oblong  slab  of  wood,  somewhat  larger  than  the  microscopic 
slide,  with  a  circular  aperture  and  ledge  to  support  the  glass 
"•disk,  enable  us  to  examine  the  sublimate  under  the  microscope, 
and  a  similar  piece  of  thick  cardboard,  with  a  hole  punched  in 
the  Centre  of  it,  serves  for  the  mounting  of  the  preparation. f 
By  this  mode  of  procedure  I  have  obtained  sublimates  of 
Veratria  and  sola-nine,  which  correspond  closely  with  the  descrip- 
tions and  photographs  given  by.Helwig;  but,  in  the  case  of 
strychnia  and  morphia,  I  have  got  very  distinct  and  extremely 
beautiful -crystalline  sublimates  (not  exceptional,  but  as  the  rule,) 
where  he  has  failed  ;J  and  though  I  am  not  yet  prepared  to 
assert  positively  that  the  strychnia  and  morphia  sublimates  can 
always  be  distinguished  by  their  crystalline  forms  alone,  I  am 
able  to  correct  the  statements  contained  in  the  following  pass- 
ages 
"It  (the  sublimate  of  morphia)  consists  of  perfectly  homo- 
geneous spots  of  round,  very  sharply-defined  granules,  closely 
packed  together,  which,  when  magnified  a  hundred  and  sixty 
times,  are  transparent,  but  among  which  no  trace  of  a  crystal- 
line formation  can  be  discovered,  (p.  9)  and  "  Examined 
microscopically,  a  sublimate  of  strychnia  is  not  to  be  distin> 
guished  from  a  sublimate  of  morphia  ;  precisely  the  same  spots 
of  round  transparent  granules,  without  trace  of  crystalline 
formation  (p.  21)." 
My  object,  in  the  present  Communication,  is  to  draw  atten- 
tion to  a  new  method  of  procedure,  which,  even  if  it  should  fail 
tO  realize  the  sanguine  expectations  of  Dr.  Helwig,  will  certainly 
*As  the  disks  of  glass -can  only  be  conveniently rcut  by  a  revolving 
diamond,  which  few  glaziers  possess,  it  may  be  well  to  mention  that  they 
may  be  procured  of  Mr.  Eade,  130  High  Holborn,  at  a  cost  of  two  shil- 
lings the  gross. 
t  When  dealing  with  larger  quantities  (such  as  a  grain  or  more)  of  the 
alkaloids,  the  short  specimen  tube  may  be  substituted  for  the  porcelain 
and  microscopic  cell-glass.  But  the  results  are  far  from  satisfactory; 
fand  it  would  certainly  be  better  to  sublime  successive  small  portions  of 
a  hundredth  of  a  grain  or  less  from  the  porcelain. 
%  I  have  also  obtained  very  fine  crystalline  sublimates  from  -the  new 
alkaloid  Oryptopia. 
