Am.  Jour.  Pharm.  \ 
March,  1899.  / 
Lit  Ilium  Citrate. 
137 
Buchner,  at  500  C. ;  while  Kossman  found  it  to  melt  at  400  C. ;  but 
in  the  last  case  the  melting-point  was  very  likely  lowered  by  the 
substance  being  contaminated  with  fat. 
^  LITHIUM  CITRATE. 
By  Lyman  F.  KEBtER. 
Research  Committee  B,  Pharmacopoeia  Revision. 
t  This  is  the  most  important  lithium  salt,  excepting  the  carbonate^ 
now  in  use.  It  is  used  quite  extensively  and  has  been  the  subject  of 
several  investigations.  But  there  seems  to  be  considerable  difference 
of  opinion  as  to  whether  the  hydrous1  or  the  anhydrous  salt  is  the 
proper  article.  The  U.S. P.  recognizes  the  anhydrous,  while  the 
1898  Br.P.  recognizes  the  hydrous.  If  it  is  the  aim  of  the  Pharma- 
copoeias to  recognize  that  article  which  is  of  a  constant  com- 
position, the  choice  lies  with  the  crystalline  product.  It  has  been 
shown  a  number2  of  times  that  the  product  containing  the  full 
quota  of  water  of  crystallization  is  uniform  in  composition,  while 
the  so-called  anhydrous,  may  contain  from  1  to  4  molecules  of  water 
of  crystallization.    It  is  anything  but  uniform. 
In  order  to  get  more  information  along  this  line  the  writer  col- 
lected samples  from  various  parts  of  the  United  States  and  made 
some  of  the  crystalline  product  on  both  the  large  and  small  scale. 
The  results  are  collected  in  the  table  on  next  page  : 
1  Hydrous,  as  here  used,  means  the  salt  with  4  molecules  of  water  of  crystalli 
zation. 
2 1875,  J.  Umney,  "Year-Book  of  Pharm.,"  559. 
1883,  C.  Thompson,  Pharm.  Jour,  and  Trans. ;  Am.  Jour.  Pharm.,  55,314. 
