36 
Varieties. 
J  Am.  Jour.  Pharrn: 
\       Jan.  1876. 
rota j y.  The  flocculent  precipitate,  amounting  to  about  36  per  cent.,  gives  the  reac- 
tions of  cellulose  with  iodine,  but  in  the  analysis  the  carbon  comes  out  slightly 
higher  than  that  required  by  the  formula  C6H10O5.  This  is  probably  due  to  the 
presence  of  some  impurity  similar  to  the  compound  found  in  fir-wood  by  J.  Erd- 
mann. 
Linseed  Mucilage. — Linseed  treated  in  a  manner  similar  to  that  above  described 
gave  numbers  corresponding  with  the  formula  C6H10O5,  or  the  same  as  that  of  cellu- 
lose. When  boiled  with  dilute  sulphuric  acid,  it  decomposes  like  quince  mucilage^ 
but  with  much  greater  difficulty,  gum  and  sugar  being  formed,  and  the  former  being 
gradually  converted  into  the  latter  by  long-continued  boiling  The  insoluble  resi- 
due is  very  much  smaller  than  with  quince  mucilage,  being  only  about  4  per  cent. 
Fleabane  Mucilage. — This  has  the  formula  C36H58029.  Boiled  with  acid,  it  decom- 
poses like  the  other  mucilages,  yielding  gum  and  sugar,  but  in  this  instance  the  gum 
is  completely  converted  into  dextrorotary  sugar  by  long-continued  boiling. 
From  these  results  the  authors  infer  that  in  quince  mucilage  the  cellulose  exists  in 
combination  with  the  gum,  since  no  cellulose  can  be  distinguished  as  such  by  micro- 
scopical examination,  and  as  the  two  substances  exist  in  the  ratio  1  :  2,  it  is  most 
probably  a  true  chemical  compound  : 
C6H10O5       +       2C6H10O5       =        C18H28014       +  H20. 
Cellulose.  Gum.  Mucilage. 
It  has  yet  to  be  determined  whether  the  other  two  mucilages  are  distinct,  or 
whether  they  are  compounds  of  cellulose  and  gum  in  the  proportion  1  :  2,  mixed 
with  excess  of  gum  :  the  different  behavior  of  the  fleabane  mucilage  when  treated 
with  acid  from  that  of  the  quince  would,  however,  seem  to  preclude  this  view. 
The  concluding  portion  of  the  paper  is  occupied  with  theoretical  speculations  as 
to  the  manner  in  which  the  carbohydrates  may  become  transformed,  the  one  into 
the  other — Jour.  Chem.  Soc.  [Lond.],  Nov.,  1875,  from  Annalen  der  C/iemie,  clxxv, 
205—226. 
Mutual  Displacement  of  Acetic  and  Formic  Acids.  By  H.  Lescceur. — 
It  is  generally  known  that  formic  acid  can  expel  acetic  acid  from  its  combinations, 
but  inversely  acetic  acid  has  been  found  also  to  displace  formic  acid.  When  a 
mixture  of  acetic  acid  and  sodium  formate  is  distilled,  a  very  considerable  quantity 
of  formic  acid  is  found  in  the  distillate,  but  even  with  a  large  excess  of  acetic  acid 
complete  decomposition  of  the  formate  was  never  obtained. 
The  majority  of  the  formates  soluble  in  acetic  acid  are  decomposible  in  like  man- 
ner, some  indeed  without  even  the  application  of  heat ;  thus,  potassium  formate  dis- 
solves in  acetic  acid,  and  if  allowed  to  evaporate  spontaneously,  gives  a  residue  con- 
sisting mainly  of  potassium  acetate.  There  would  appear,  therefore,  to  be  an 
equilibrium  established  between  the  quantity  of  formic  acid  set  at  liberty,  and 
acetate  formed  in  a  manner  similar  to  that  which  has  been  noticed  in  many  other 
instances  b*y  different  operators. 
When  one  part  of  sodium  formate  is  dissolved  with  heat  in  five  parts  of  mono- 
hydrated  acetic  acid,  crystals  are  obtained  on  cooling,  which  were  found  to  have 
the  composition,  NaC2H302.2C2H402  -+-  NaCH02.2CH202.— Journ.  Chem.  Soc, 
November,  1875,  fr°m  Bull.  Soc.  Chim.  [2],  xxiii.  259. 
