ON  CRYSTALLIZED  ACETATE  OF  MAGNESIA. 
245 
which  troubled  him,  and  this  dried  beef  was  one  of  them,  and  con- 
tained not  less  than  ten  or  fifteen  grains  of  sulphate  of  strychnia. 
It  must  have  been  in  the  stomach  one  hour  before  she  was 
known  to  be  sick.  Mr,  Hannay  gave  her  a  dose  of  oil  (castor) 
at  once,  which  no  doubt  protected  the  stomach  and  prevented 
the  absorption  of  the  poison  in  a  dangerous  quantity,  until  my 
arrival.  The  negro  Woman  took,  in  all,  3j  bottles  olive  oil ;  the 
child  nearly  1  bottle. — Amer.  Jour,  of  the  Med.  Sciences. 
Tausse  Point,  St.  Martin's,  La.,  June  6,  1854. 
ON  CRYSTALLIZED  ACETATE  OF  MAGNESIA. 
By  Karl  yon  Hauer. 
Acetate  of  magnesia  is  mentioned  in  all  the  text-books  of  che- 
mistry as  a  salt  which  is  crystallizable  only  with  great  difficulty  ; 
and  when  its  aqueous  solution  is  evaporated,  generally  remains 
in  the  form  of  a  bitter,  sticky,  and  deliquescent  gum.  In  the 
dehydrated  state,  according  to  the  analyses  of  Wenzel  and 
Richter,  its  constitution  is  0l  H3  MgO4.  According  to  Connell, 
it  is  distinguished  from  formiate  of  magnesia  by  its  incapability 
of  crystallization  and  its  deliquescence. 
The  author  prepared  this  salt  by  dissolving  caustic  magnesia 
in  acetic  acid.  If  the  aqueous  solution  thus  obtained  be  evapo- 
rated, it  will  become  concentrated  until  it  attains  the  consistence 
of  a  syrup,  and  will  at  last  become  dry,  without  presenting  any 
formation  of  crystals.  This  is  the  case  even  when  the  evapora- 
tion is  effected  by  a  moderate  heat.  But  if  the  concentrated 
solution  of  the  salt  be  left  to  evaporate  spontaneously  at  the 
ordinary  temperature  of  a  room,  it  generally  acquires  a  crystal- 
line film  on  the  surface,  which  gradually  becomes  very  solid,  and 
so  close  that  it  to  a  certaint  extent  hermetically  seals  the  solu- 
tion, and  consequently  prevents  its  further  evaporation.  It  is 
but  rarely  that  crystallization  commences  at  the  bottom  of  the 
vessels,  and  the  surface  of  the  fluid  remains  alway  free,  but  under 
these  circumstances  the  largest  crystals  are  obtained.  This 
mode  of  preparation,  however,  depends  almost  entirely  upon 
chance.  The  author  therefore  tried  concentrating  the  solution  of 
the  salt  very  strongly  by  heat,  and  then  letting  it  cool  as  slowly* 
as  possible.   In  this  way  he  always  succeeded  in  obtaining  crystals 
