MYRONATE  OF  POTASSA  IN  BLACK  MUSTARD-SEED.  539 
Dissolve  the  nitrate  of  potassa  in  the  nitric  acid,  and  then  add 
the  sulphuric  acid  ;  mix  well  together,  and,  while  warm,  im- 
merse the  cotton  three  minutes ;  transfer  to  a  basin  of  water, 
and  wash  well  until  all  traces  of  acid  disappear ;  dry  in  the 
open  air,  and  dissolve  in  thirty  times  its  weight  of  a  mixture  of 
twenty-five  parts  of  ether  and  five  of  alcohol  of  95  per  cent. 
The  advantages,  it  will  be  observed,  are  simply  these  :  the 
acid  being  1.40  can  always  be  obtained,  (being  about  the  sp.  gr. 
of  chemically  pure  nitric  acid) ;  the  easy  immersion  of  the  cot- 
ton ;  having  avoided  the  excessive  quantity  of  potassa  and  an 
entire  absence  of  the  noxious  red  fumes  of  nitrous  acid,  which, 
by  the  process  of  the  Pharmacopoeia,  have  often  ruined  my 
cotton. — Ibid. 
ON  THE  MYRONATE  OF  POTASSA  IN  BLACK  MUSTARD-SEED. 
By  Dr.  S.  von  Thielau, 
The  author  being  desirous  of  studying  the  properties  of  myro- 
sine  and  myronic  acid,  followed  Bussy's  directions  for  obtaining 
these  substances,  as  published  by  him,  in  the  Journal  de  Pharmacie, 
1840,  xxvi.,  39  ;  his  results,  however,  are  so  much  at  variance  with 
those  of  Bussy,  that  most  of  the  statements  of  the  latter  are  con- 
tradicted.   Yet  the  following  were  found  correct : 
1.  The  aqueous  extract  of  the  alcoholic  extract  of  black  mus- 
tard generates  with  white  mustard  sulphocyanuret  of  allyl,  oil  of 
mustard  :— the  result  is  the  same,  whether  the  white  mustard  in  sub- 
stance, its  aqueous  infusion,  or  the  impure  myrosine  is  used. 
2.  Neither  yeast,  synaptase,  nor  any  other  ferment,  (myrosine  ex- 
cepted,) is  able  to  produce  the  oil  of  mustard  with  the  aqueous  ex- 
tract of  the  black  seed. 
3.  The  extract  is  decomposed  with  the  evolution  of  sulphuretted 
hydrogen,  if  it  is  kept  at  a  temperature  above  100Q  C,  (212°  F.,) 
after  some  time  no  oil  is  generated  on  the  addition  of  white  mustard. 
The  author  experimented  with  25  lbs.  of  black  mustard-seed  which 
was  ground,  the  fixed  oil  expressed,  and  then  exhausted  with  86 
per  cent,  alcohol,  at  first  at  ordinary  temperature,  afterwards  at68Q 
C,  (154°  F.  ;)  the  alcohol  was  regained  by  careful  distillation,  and 
one  pound  of  syrup  was  obtained,  which  was  so  stiff  as  not  to  move 
