^°'Mar'''i882'™  }     Practical  Notcs  fvom  Foreign  Journals.  117 
air-dry  powder  is  treated  for  24  hours  with  3J  parts  of  pure  hydro- 
chloric acid  and  with  frequent  agitation,  but  without  heat,  when  the 
liquid  is  filtered;  the  proper  specific  gravity,  1*34  to  1*36,  is  obtained 
either  by  dilution  with  hydrochloric  acid  or  by  evaporation  in  a  water 
bath. 
Thus  prepared  it  is  a  colorless  or  pale  yellowish  liquid,  which  is 
completely  volatilized  by  heat,  and  when  diluted  with  5  parts  of  water 
yields  a  perfect  solution  on  the  careful  addition  of  sulphuric  acid 
(absence  of  lead).  Treated  with  an  excess  of  ammonia  and  filtered, 
the  liquid  is  clear  and  not  blue  (absence  of  copper).  When  heated  to 
50  or  60°C.  (122  to  140°F.)  a  current  of  sulphuretted  hydrogen 
should  not  cause  the  separation  of  either  sulphur  or  sulphide  of  arse- 
nic.— Archiv  d.  Phar.,  Nov.,  1881,  p.  347. 
Extr actum  Kramerice. — Prof.  E.  A.  Vander  Burg  has  made  a  num- 
ber of  experiments  with  the  view  of  determining  the  causes  of  the 
dilferent  behavior  of  commercial  extract  of  rhatany.  The  Peruvian 
root  exhausted  by  cold  water  yielded  10*5  per  cent.,  and  by  decoction 
18*5  per  cent,  of  extract,  while  Savanilla  rhatany  gave  14' 75  and 
20*50  per  cent.  Of  these  extracts  that  of  the  Peruvian  root,  prepared 
with  cold  water  and  by  evaporation  in  vacuo,  was  of  a  light  red  color 
(not  brown),  readily  and  completely  soluble  in  water,  had  the  strong- 
est astringent  taste,  and  gave  the  strongest  reactions  for  tannin ;  a  one 
per  cent,  solution  yielded  with  lead  acetate  a  nearly  white,  slightly 
rose-colored  precipitate,  with  ammonia  a  bright  blood-red  color,  and 
with  lime  water  a  light  red  precipitate.  The  corresponding  reactions 
with  the  other  extracts  were  mostly  much  darker,  as  were  also  the  pre- 
cipitates with  cinchonine  sulphate  and  with  tincture  of  iodine.  For 
the  preparation  of  syrupus  iodotannicus  O'l  gram  iodine  was  dissolved 
in^2  cc.  alcohol,  of  spec.  grav.  '828,  and  the  solution  mixed  with  0*4 
gram  of  extract,  previously  triturated  with  4  cc.  water;  with  the 
extract  prepared  by  cold  water  and  evaporation  in  vacuo  the  reaction 
of  free  iodine  had  completely  ceased  in  24  hours,  while  it  w^as  still  evi- 
dent with  all  the  other  extracts  after  six  weeks,  evidently  due  to  the 
decomposition  of  a  portion  of  the  tannin  during  tlip  preparation. 
No  characteristic  difference  could  be  observed  b<Livveen  the  extracts 
prepared  from  the  cold  infusion  by  evaporation  at  the  ordinary  tem- 
perature, in  the  water-bath  or  over  the  naked  fire ;  nor  between  the 
extracts  prepared  from  decoctions  of  the  root  and  evaporated  in  the 
manner  indicated ;  the  latter  extracts  were  invariably  dark  in  color, 
