538  Gleanings  from  the  Foreign  Journals,  {AmbJe°cU,r'J7h6arm' 
distinction  between  ferrous  and  ferric  salts,  by  metaphosphoric  acid,  is 
well  defined. 
The  large  excess  of  alkali  required  to  give  a  precipitate  in  the  mix- 
ture of  metaphosphoric  acid  and  certain  salts,  as  aluminium  and  mag- 
nesium salts,  may  be  due  to  the  formation  of  soluble  double  metaphos- 
phates,  representing  polymeric  modifications  of  the  monobasic  acid. 
The  proportion  of  neutralized  phosphoric  acids  (sodium  phosphates) 
which  can  be  present  in  solutions,  without  causing  precipitates  in  salt 
solutions,  is  a  question  of  interest,  because  of  the  presence  of  alkaline 
phosphate  in  the  glacial  acid  and  solutions  made  therefrom. 
It  was  to  determine  this  question,  and  also  to  settle  some  doubts  as 
to  how  far  the  metallic  precipitates,  stated  in  the  books  for  the  free 
phosphoric  acids,  have  been  due  to  unknown  presence  of  alkaline  phos- 
phates, that  these  experiments  were  made. 
University  of  Michigan,  November  14,  1876. 
GLEANINGS  FROM  THE  FOREIGN  JOURNALS. 
BY    THE  EDITOR. 
Composition  of  Xanthium  Spinosum. — Yvon  and  Nocard  have  obtained 
from  100  parts  of  the  air-dry  plant  11*828  water,  76*518  of  organic 
and  11*654  parts  of  inorganic  matter.  Among  the  organic  constituents 
was  found  10*632  starch,  0*808  glucose,  2*040  chlorophyll  and  resin 
soluble  in  ether,  the  remaining  63*038  consisting  of  cellulose,  acids  and 
probably  an  alkaloid.  The  mineral  constituents  were  those  usually 
found  in  plants,  lime  (2*454  p.)  and  magnesia  (2*436  p.)  preponderating. 
Not  a  trace  of  alkaloid  could  be  detected  in  the  decoction  with  acidu- 
lated water,  which  had  been  treated  with  milk  of  lime,  and  the  precipi- 
tate digested  with  alcohol  and  chloroform  ;  but  by  using  alcohol,  and 
following  the  process  of  Stas,  liquids  were  obtained,  which  yielded 
precipitates  with  several  of  the  general  reagents  for  alkaloids.  But 
similar  reactions  may  be  obtained  on  treating  sandarac,  olibanum  and 
other  resins  in  a  similar  manner. — Rep.  de  Phar.,  1876,  p.  546. 
Olive-tree  bark  as  a  febrifuge  is  recommended  by  L.  Thibon,  of 
Tournai,  who  has  prepared  from  it  a  principle  named  oliverin,  which 
he  prepares  as  follows  :  The  aqueous  decoction  of  the  bark  is  evapo- 
rated to  a  syrupy  consistence  ;  this  is  precipitated  by  strong  alcohol, 
and  the  filtrate  again  by  the  careful  addition  of  oxalic  acid.  The 
