^NoviX/i9iT' }     -4ssay  Processes  of  the  U,  S.  P.  517 
hence  the  necessity  of  first  reducing  the  drug  to  a  fine  powder. 
If  the  sample  of  jalap  consists  of  tubers,  these  are  crushed  in  an 
iron  mortar,  then  ground  in  a  mill  until  the  material  passes  through 
a  No.  30  sieve,  and  finally  pulverized  by  turning  for  several  hours 
in  a  pebble  mill. 
(2)  If  strong  alcohol  is  added  directly  to  a  finely  powdered 
drug,  the  particles  contract  to  such  a  degree  that  the  menstruum 
percolates  but  slowly,  if  at  all.  When  the  powder  is  moistened 
with  water  as  described  above,  it  swells  to  nearly  twice  its  original 
volume,  the  particles  coalesce  to  form  tiny  granules  which  persist 
even  after  the  addition  of  alcohol  and  heating,  and  the  subsequent 
draining  and  washing  of  the  drug  in  the  percolator  proceeds  with 
great  rapidity. 
(3)  The  proportions  of  alcohol  and  water  employed  for  the  hot 
maceration  are  such  as  to  produce  a  menstruum  containing  about 
90  per  cent,  absolute  alcohol,  which  appears  to  be  a  more  efficient 
solvent  than  an  alcohol  of  higher  percentage.  , 
(4)  A  pestle  is  easily  made  by  heating  the  end  of  a  glass  rod 
12  mm.  in  diameter  quite  hot,  pressing  firmly  against  a  flat  metal 
surface,  then  smoothing  and  rounding  on  a  stone. 
THE  ASSAY  PROCESSES  OF  THE  U.S.P.^ 
By  a.  R.  L.  Dohme  and  H.  Engelhardt. 
On  various  occasions  we  have  pointed  out  that  several  assay 
processes  of  the  present  U.S. P.  are  very  much  in  need  of  being 
thoroughl}  revised,  both  because  the  methods  are  rather  cumber- 
some, and  the  results  are  far  from  giving  the  true  percentage  of  the 
active  principle.  Since  the  methods  are  going  to  be  thoroughly 
discussed  at  the  coming  meeting  of  the  A. Ph. A.  we  thought  it 
necessary  to  again  give  our  views  in  regard  to  the  processes, 
although  several  points  given  here  may  have  been  discussed  by  us 
on  previous  occasions. 
We  still  believe  that  the  aliquot  part  method,  when  worked  with 
precaution,  gives  more  accurate  results  than  the  percolation  method. 
The  drug  is  more  thoroughly  exhausted  by  shaking  with  the  men- 
^  Read  at  the  Boston  meeting  of  the  American  Pharmaceutical  Associa- 
tion, August,  191 1. 
