AmMa°rch^8b87!'m'}    Conversion  of  Glucoses  into  Dextrins.  151 
precipitated  by  alcohol,  solution  and  precipitation  being  repeated  sev- 
eral times.  The  product  was  then  dissolved  in  water,  decolorized  by 
animal  charcoal,  the  solution  concentrated  by  evaporation  in  a  vacuum 
on  the  water-bath,  and  then  allowed  to  evaporate  in  a  vacuum  at  the 
ordinary  temperature.  The  product  thus  obtained  is  a  white  powder 
which  resembles  ordinary  white  dextrin,  is  very  hygroscopic,  and 
forms  gummy  solutions.  Its  reducing  and  rotatory  powers  vary  with 
the  number  of  times  the  substance  has  been  redissolved  and  reprecip- 
itated.  When  prepared  by  the  method  just  described,  the  dextrin 
contains  a  small  proportion  of  fermentable  sugar,  which  can  be  re- 
moved by  treatment  with  yeast.  After  purification  in  this  way,  one 
product  had  a  reducing  power  of  17*8  per  cent.,  whilst  its  rotatory 
power  for  [a]i>  =  -f  97*48. 
The  dextrin  obtained  in  this  Avay  has  the  composition  3C6H10O5  -j- 
H20,  and  belongs  to  the  class  of  achroodextrins.  Its  general  prop- 
erties resemble  those  of  the  dextrin  obtained  by  Musculus  by  the  ac- 
tion of  sulphuric  acid  on  glucose  in  presence  of  alcohol,  but  it  has  a 
lower  rotatory  and  reducing  power.  It  is  not  colored  by  iodine,  is  un- 
affected by  infusion  of  malt,  and  undergoes  hydration  somewhat 
slowly  when  boiled  with  dilute  acids.  The  glucose  formed  from  it  by 
the  action  of  acids  is  readily  fermentable. 
The  alcoholic  liquid  from  which  the  dextrin  has  been  precipitated 
contains  other  dextrins  with  higher  reducing  powers,  together  with  a 
fermentable  sugar  which  is  found  by  Fischer's  reaction  with  phenyl- 
hydrazine  and  sodium  acetate  to  be  a  mixture  ofglucose  and  maltose. 
Galactose  from  milk-sugar  behaves  like  dextrose,  and  yields  a  gal- 
actodextrin  which  resembles  glucodextrin.  Its  reducing  power  in 
terms  of  glucose  is  10  per  cent.,  and  its  rotatory  power  for  [a]D  = 
-f  80. — Jour.  Chem.  Soc,  1886,  p.  1003,  Compt.  rend,  ciii,  7-16. 
GLKANINGS  IN  MATERIA  MEDICA. 
By  the  Editoe. 
Cantharides  as  a  preventive  of  hydrophobia. — According  to  Brit. 
Med.  Jour.,  a  Russian  physician,  Dr.  Karchewski,  has  treated  three 
persons,  who  had  been  bitten  by  a  rabid  wolf,  with  cantharides  plaster 
applied  to  the  wounds,  giving  at  the  same  time  one  grain  of  pow- 
dered cantharides  daily  for  one  week.  After  seven  months  no  symp- 
toms of  rabies  had  appeared. 
