212    ON  THE  KINDS  OP  RHUBARB  IN  RUSSIAN  COMMERCE. 
salt,  continue  the  heat  until  the  excess  of  acid  is  expelled,  and, 
if  preferred  in  crystallized  form,  re-dissolve  in  distilled  water 
and  crystallize. The  process  of  our  own  Pharmacopoeia  will 
yield  a  pure  salt  without  loss  of  silver,  if  the  latter  is  used  in  a 
nearly  pure  state,  the  nitrate  of  other  metals  which  are  likely  to 
be  present  being  decomposed  by  fusion  ;  but  the  filtration  through 
paper  of  the  solution  of  the  pure  salt  is  objectionable,  since  the 
resulting  crystals  will  be  very  easily  blackened  on  exposure ; 
powdered  glass  or  gun  cotton  ought  to  be  substituted.  Our 
Pharmacopoeia  is,  moreover,  inconsistent  in  directing  absolutely 
pure  metallic  silver  and  nitric  acid,  and  assuming  the  presence 
of  other  ^etals  in  preparing  the  nitrate. 
(To  be  continued.) 
ON  THE  KINDS  OF  RHUBARB  AT  PRESENT  IN  RUSSIAN 
COMMERCE. 
By  Adolph  Fero,  of  Moscow. 
The  supply  of  rhubarb  is  at  present  a  most  important  ques- 
tion to  the  Russian  apothecary.  After  having  been  compelled 
for  centuries  to  fill  our  wants  from  the  magazines  of  the  govern- 
ment, and  there  obtaining  only  the  best  quality,  the  so-called 
Radix  Rhei  Moscovitici,  brought  by  Bucharian  merchants  to 
Kiachta  and  there  examined  and  bartered  by  the  crown,  we  see, 
for  several  years  past,  this  traffic  cut  oif,  the  supplies  of  the 
government  completely  exhausted  and  yet  no  prospect  for  re- 
establishing that  trade. 
Although  the  prohibition  to  obtain  rhubarb  from  foreign  coun- 
tries has  not  been  rescinded,*  this  measure  will  sooner  or  later 
become  imperative,  and  the  question  will  then  arise,  what  new 
kinds  of  rhubarb  may  be  obtainable  by  us  and  what  is  their  com- 
parative value,  and  how  do  they  compare  with  the  crown  rhu- 
barb, as  formerly  obtained  ? 
Having  been  ordered  by  the  government  to  Kiachta  and  em- 
ployed there  as  pharmacist  at  the  inspecting  office  for  rhubarb,  I 
had  frequent  occasion  to  study  the  conditions  of  the  trade  in 
rhubarb  and  to  examine  the  kinds  received.    Since  that  time  my 
*  Apothecaries  must  even  now  obtain  rhubarb  from  other  sources. 
