A%Jp0rnr;i9ooarm"}    Recent  Literature  Relating  to  Pharmacy.  i8r 
calcium  carbonate,  yielded  the  calcium  salt  of  the  corresponding 
acid,  C7H1406,  which  the  writer  calls  digitalonic  acid.  This  salt  dif- 
fers from  itsmetameric  salt  of  the  digitoxose  acid  mentioned  above, 
by  charring  without  melting,  at  ioo°. 
With  A.  Windaus,  Professor  Kiliani  investigated  digitalein,  a 
product  of  the  commercial  German  digitalin,  the  degree  of  purity 
of  the  product  being  estimated  at  each  stage  of  its  extraction  by 
physiological  tests  on  the  frog.  The  extreme  care  in  this  concen- 
tration is  especially  noteworthy. 
Starting  with  I  kilo  of  the  commercial  digitalin,  this  was  freed 
from  digitonin,  "  digitalinum  verum  "  and  impurities  by  Kiliani's 
method  of  extraction  and  this  concentration  was  found  to  effect 
heart  systole  on  a  frog  in  doses  of  7  milligrammes.  This  product 
was  dialyzed  and  the  dried  dialysate  (yield,  40  grammes)  was  found 
fatal  to  the  frog  in  doses  of  3  milligrammes.  This  dialysate  was 
further  purified  by  precipitation  with  tannin  and  subsequent  separ- 
ation of  the  tannin  from  the  precipitate  with  zinc  oxide.  This  pro- 
duct (weight,  15  grammes)  was  further  purified  by  fractional  crystal- 
lization with  alcohol  and  ether.  The  first  fraction  produced  no 
systole,  the  second  was  not  tried,  but  the  remainder,  on  evaporation 
of  the  solvent  (yield,  4  to  5  grammes),  worked  systole  in  doses  of  0-4 
milligramme.  This  product,  digitalein,  was  obtained  in  too  small 
quantities  to  be  fully  examined.  It  was  analyzed,  but  no  definite 
formula  could  be  deduced  from  the  combustion  figures.  It  showed 
glucosidal  properties  and  its  aqueous  solution  had  acid  reaction. 
Further  investigation  seemed  to  show  that  it  was  a  lactone,  becom- 
ing, by  hydration  in  solution,  an  inert  acid. 
Both  infusion  and  tincture  of  digitalis  contain  digitalein;  the  in- 
fusion from  10  kilos  leaves  yielding  2  grammes  of  a  product,  0-6 
milligramme  of  which  produced  systole  on  the  frog  ;  while  the  alco- 
holic extract  from  10  kilos  yielded  1 50  grammes  of  a  body  producing 
systole  in  doses  of  1*5  milligrammes.  Further  concentration  of  the 
latter  body  was  too  wasteful  to  be  successful. 
The  last  article  in  the  interesting  series  was  one  on  digitogenin 
and  its  constituents.  H.  V.  A. 
THE  REFRACTOMETER  APPLIED  TO  VOLATILE  OILS. 
Taking  as  text  the  statement  of  Gildemeister  and  Hoffmann,  in 
their  work  in  volatile  oils,  that  the  refractometer  has  but  little  value 
