24         ON  A  TEST  FOR  THE  RESIN  OF  CANNABIS  INDICA. 
In  another  sample  from  the  same  House  in  ounce  jars,  the  pro- 
portion of  aqueous  extractive  was  hardly  noticeable.  Another 
sample,  the  origin  of  which  was  not  known,  and  which  was  quite 
old,  had  a  solid  consistence,  almost  black  color,  and  produced 
powerful  effects  at  the  time  it  was  tried  therapeutically  many 
years  ago.  No  feature  of  this  extract  is  more  marked  than  its 
softness.  After  a  pretty  thorough  examination  of  the  subject,  I 
believe  this  to  be  chiefly  due  to  fixed  oil  of  the  hemp  seeds, 
which  the  tops  often  contain  sufficiently  developed  to  yield  oil, 
and  which  is,  to  a  greater  or  less- extent,  extracted  by  the  spirit, 
and  being  miscible  with  the  resin,  they  remain  in  close  union. 
As  regards  the  extractive  matter  soluble  in  water,  its  presence 
is  easily  accounted  for,  either  by  the  use  of  alcohol  weaker  than 
•835,  or  by  following  strong  alcohol  with  weaker  spirit  to  dis- 
place the  former,  when  the  process  is  carried  too  far.  When 
officinal  alcohol  alone  is  used,  it  may  occur  by  continuing  the 
boiling  process  until  the  percentage  of  alcohol  gets  below  the 
standard  strength,  as  will  occur  with  officinal  alcohol  during  con- 
tinued digestion.  Where  the  proportion  of  matter  insoluble  in 
alcohol  is  as  great  as  40  per  cent.,  either  error  or  design  must 
have  produced  it,  as  under  no  ordinary  circumstances  will  hemp 
yield  to  alcohol  such  a  product. 
In  the  process  of  Mr.  Robertson,  of  Calcutta,  described  by 
Pereira,  in  which  the  vapor  of  alcohol  boiling  in  a  still  is  con- 
ducted into  the  top  of  a  cask  containing  the  gunjah,  with  an  ordi- 
nary condensing  worm  attached  to  the  bottom  of  the  cask,  this 
may  also  readily  occur ;  as  the  last  portions  of  vapor  from  the 
still  will  be  much  more  watery  than  the  first,  they  will  dissolve 
the  extractive  and  carry  it  down  into  the  recipient  along  with 
the  resin,  to  be  mingled  with  it  in  the  subsequent  concentration  to 
the  extractive  consistence. 
M.  Gastinel,  of  Cairo,  Egypt,  has  suggested  that  the  resin 
should  be  washed  with  water  to  rid  it  of  this  extractive. 
M.  Laneau,  of  Brussels,  after  finding  that  hemp  resin  is  much 
more  soluble  in  a  mixture  of  alcohol  and  ether  or  chloroform 
than  in  alcohol  alone,  recommends  the  hemp  to  be  exhausted  by 
percolation  with  such  a  mixture,  which  not  only  dissolves  the 
resin  better,  but  does  not  dissolve  the  inert  matter. 
