AmMayj89ifrm'}  Gleanings  from  the  German  Journals.  223 
water.  The  anhydrous  acid  CuH6Os  is  called  ellagic  acid  (the 
formula  of  which  is  generally  given  C14H809)  ;  the  hydrated  acid 
CMH10O10  is  called  ellaggenic  acid  ;  the  latter  forms  a  penta-acetyl 
derivative,  the  former  a  tetra-acetyl  derivative,  indicating  five  and 
four  hydroxyl  groups,  respectively,  in  the  acids.  In  the  fruit  there 
also  pre-exist  small  quantities  of  gallic  and  oxalic  acids. 
The  tannin  of  Myrobalans  is  also  a  mixture  of  the  two  tannins 
mentioned  above,  although  in  somewhat  different  proportions ; 
gallic  acid  in  small  quantity  is  also  present.  The  tannins  were 
separated  by  fractional  precipitation  with  lead  acetate,  subsequently 
purified  by  precipitation  with  sodium  chloride  and  solution  in  acetic 
ether. — G.  Zoelfell,  Arch,  der  Pharm.,  1 891 ,  1 23-160. 
Musk.— Th.  Wimmel  publishes  the  results  of  a  recent  exami- 
nation of  a  sample  of  musk  which  contained  about  25  per  cent, 
foreign  vegetable  matter,  chiefly  starch,  and  lost  by  drying  in  a 
water  bath,  51  percent,  moisture;  the  ash  amounted  to  only  2-5 
per  cent. — Apoth.  Ztg.  1 891,  154. 
Assay  of  mercurial  ointment. — A  moderately  wide  test  tube  is 
filled  to  within  one  inch  from  the  mouth  with  either  of  the  solu- 
tions :  Sodium  nitrate  I*  and  water  2-5,  or  magnesium  sulphate  1 
and  water  2  ;  these  solutions  must  be  exactly  neutral.  From  4-6 
gms.  of  the  ointment  are  next  placed  in  the  test  tube  and  this  then 
put  in  a  water  bath  until  the  fat  melts  and  forms  a  clear  layer  above 
the  aqueous  solution  ;  the  solution  having  a  higher  specific  gravity 
than  the  ointment  the  latter  will  float -and  in  melting  the  mercury 
sinks  to  the  bottom  of  the  tube.  After  the  fat  becomes  clear  a 
small  stick  is  suspended  in  the  fat  and  the  test  tube  set  aside  until 
the  contents  become  cold;  by  gently  warming  the  part  of  the  test 
tube  containing  the  fat  the  latter  can  be  withdrawn  from  the  test 
tube,  and  after  the  removal  of  the  stick,  weighed.  By  the  appear- 
ance of  the  fat  some  idea  of  its  nature  may  be  obtained.  The 
mercury,  after  pouring  off  the  saline  solution,  is  washed  several 
times  with  water,  dried  by  putting  it  in  crumpled  filtering  paper 
and  weighed.  If  the  mercury  used  was  not  pure  the  weight 
obtained  will  be  deficient,  as  the  contaminating  metals  will  gradually 
unite  with  the  fatty  acids  and,  hence,  be  found  in  the  fat.  The 
saline  solution  used  must  not  contain  even  traces  of  alkali  as  this 
would  cause  saponification  and  prevent  the  fat  from  separating  out 
perfectly. — C.  Thein,  Apoth.  Ztg.,  1891,  172. 
