192  Characters  of  Extract  of  Calabar  Bean. 
Standardized  soda  solution  (1  cc.  =  0*0133  NaHO)  used. 
L.  5  cc.  required  4-3  cc.  for  neutralization. 
B.  5  cc.  required  1*8  cc.  for  neutralization. 
C.  5  cc.  required  0*8  cc.  for  neutralization. 
We  thus  see,  in  addition  to  facts  already  recorded,  that  in  the  course 
of  time  the  nitrous  constituent  of  sweet  spirit  of  nitre  entirely  disap- 
pears; that  aldehyde,  one  of  the  most  readily  oxidizable  bodies  remains ; 
and  that  in  sweet  spirit  of  nitre  made  from  methylated  spirit,  formic 
acid  is  one  of  the  products  of  decomposition. — Phar.  Jour,  and  Trans. ^ 
Feb.  21,  1885,  p.  675. 
THE  PREPARATION  AND  CHARACTERS  OF  EXTRACT 
OF  CALABAR  BEAN.^ 
By  Adam  Gibson. 
It  having  come  under  my  notice  that  the  physical  characters  of  ex- 
tract of  Calabar  bean  varied  considerably,  I  have  been  lead  to  under- 
take the  preparation  of  the  extract  by  the  official  process  and  several 
modifications  thereof,  and  now  liave  the  pleasure  of  communicating  my 
results. 
The  extract  is  one  of  the  four  pharmacopoeial  extracts  which  are 
prepared  with  rectified  spirit.  These  extracts  are  of  a  resinous  nature 
and  are  either  partially  or  wholly  insoluble  in  water.  Upon  this 
point,  so  far  as  the  extract  under  notice  is  concerned,  there  seemed  to 
be  some  dubiety  ;  thus,  in  Squire's  "  Companion  ''  we  have  the  state- 
ment that  half  a  grain  of  extract  in  ten  nn'nims  of  water  is  used  for 
subcutaneous  injection,  thus  inferring  that  the  extract  is  soluble  in 
water,  while  Mr.  Marti ndale^  states  that  if  carefully  prepared  it  is  not 
miscible  with  water.  This  question  of  solubility  was  the  one  which 
really  underlay  the  work  upon  Avhich  I  now  report,  and  although 
there  seemed  to  be  no  doubt  Avhatever  that  from  its  nature  the  extract 
should  not  be  soluble  in  water,  still  the  fact  remained  that  some  com- 
mercial samples  are  soluble,  and  it  is  my  endeavor  now  to  show  why 
they  are  so. 
For  the  preparation  of  the  extract  the  British  Pharmacopoeia  directs  a 
1  Read  at  a  Meeting  of  the  North  British  Branch  of  the  Pharmaceutical 
Society,  January  14,  1885. 
^  "Extra  Pharmacopoeia,"  2d  edition,  p.  209. 
