Am.  Jour.  Pharm.  ) 
Dec,  1, 1873.  j 
Gleanings  from  the  European  Journals. 
537 
tion  than  citrate  of  magnesium.  He  recommends  to  heat  a  small 
quantity  of  tartaric  acid  in  a  porcelain  or  silver  capsule  over  a  slow- 
fire,  until,  with  occasional  agitation,  it  fuses,  when  more  tartaric  acid 
is  added  in  small  quantities,  with  the  precaution  not  to  reduce  the 
temperature  too  much,  so  as  to  avoid  the  solidification  and  subse- 
quent burning  of  the  mass.  When  sufficient  acid  has  been  added, 
the  same  heat  is  continued  until  the  whole  has  become  completely 
liquefied,  when  it  is  of  a  light  amber  color  and  entirely  converted 
into  the  metatartaric  acid.  It  is  then  removed  from  the  fire,  and 
ivhen  it  has  acquired  a  suitable  consistence,  it  is  formed  into  flat 
cakes,  which  are  to  be  kept  in  well  stoppered  bottles,  the  modified 
acid  being  very  hygrometric. 
To  prepare  the  purgative  solution,  a  portion  of  the  requisite  water 
is  added  to  the  mixed  acid  and  carbonate  of  magnesium,  all  heat 
being  cautiously  avoided  to  prevent  the  acid  from  passing  again  into 
the  state  of  ordinary  tartaric  acid,  which  would  precipitate  as  tar- 
trate of  magnesium.  The  solution  is  effected  in  a  few  minutes,  and 
keeps  unaltered  for  several  weeks.  The  author  gives  the  following 
proportions  for  making  this  solution  extemporaneously  : 
Modified  tartaric  acid,  13,  17,  20,  23,  27,  30,  33,  3?,  40,  43,  47  grams. 
Carbonate  of  magnesium,  7,  8, 10, 12, 13, 15,  17,  18,  20,  22,  23  " 
— L'  Union  pharm.,  Sept.,  1873. 
New  process  for  tar  water. — L.  Pommier  prepares  a  concentrated 
tar  water  by  macerating  in  a  covered  vessel  for  eight  days  a  mixture 
consisting  of  ten  parts  each  of  Norwegian  tar  and  ammonia  water, 
and  of  one  hundred  parts  of  water;  the  mixture  is  then  boiled  to 
expel  the  excess  of  ammonia,  then  cooled  and  filtered.  Thus  pre- 
pared, it  has  a  mild  alkaline  reaction  to  litmus,  and  may  be  diluted 
as  required. — Ibid. 
Preparation  of  pure  metallic  silver. — R.  A.  Wawrinsky  has  ob- 
served that  carbonate  of  calcium,  employed  to  precipitate  the  copper 
from  the  nitric  acid  solution  by  Gra3ger's  method,*  will  invariably 
precipitate  some  silver.  At  the  suggestion  of  Prof.  Almen  he  em- 
ployed carbonate  of  magnesium,  and  found  that  copper  nitrate  is 
gradually  precipitated  by  carbonate  of  magnesium  at  the  ordinary 
temperatures,  while  silver  nitrate  is,  under  the  same  circumstance, 
affected  only  after  a  long  time.    If  the  mixture  is  kept  at  between 
*See  American  Journal  of  Pharmacy,  1872,  p.  277. 
