ADecemberPi9i5Q" }  Concerning  Two  Sweet-tasting  Drugs.  555 
polarization  effects.  A  vast  amount  of  work  has  since  been  done  in 
the  realm  of  physical  chemistry  on  conductivity  measurements,  a 
review  of  which,  however,  is  outside  the  scope  of  this  paper.  For 
a  clear  and  concise  discussion  of  this  subject  see  Jones  ('09),  Walker 
('10),  or  Findlay  ('10). 
(To  be  continued.) 
CONCERNING  TWO  SWEET-TASTING  DRUGS* 
By  Professor  R.  Robert,  Rostock.  Germany. 
Professor  Robert,  in  a  lengthy  paper,  discusses  the  value  of  the 
general  chemical  formula  (CNH2N.8O10)  applied  by  him  to  saponins  as 
a  means  by  which  saponin-like  substances  may  be  distinguished  from 
other  plant  principles  without  the  aid  of  biological  tests,  and  gives 
several  illustrations  to  prove  the  correctness  of  his  statement. 
Research  work  on  this  class  of  drugs  along  biological  lines,  he 
says,  has  thus  far,  in  every  instance,  verified  the  chemical  identifica- 
tion, inasmuch  as  all  the  substances  belonging  within  the  range  of 
this  general  formula  have  proved  biologically  active  when  tested. 
At  present  the  whole  series  from  C15H22O10  to  C26H44O10  is  com- 
plete, some  members  even  being  represented  by  several  saponins. 
All  in  all,  about  forty  different  substances  belong  to  this  series,  some 
of  which  appear  to  be  anhydrides,  while  others  again  seem  to  be 
hydrates  of  the  general  saponin  formula.  Professor  Robert  recog- 
nizes the  fact  that  there  are  still  other  saponins  belonging  to  other 
general  formulae;  nevertheless,  by  far  the  greater  majority  thus  far 
studied  belong  within  the  range  of  this  general  formula.  Recent 
investigation  has  added  two  more  plant  principles,  viz.,  convallarin 
and  eupatorin,  to  this  series. 
Convallarin  with  the  chemical  formula  C34H6201:L,  if  written 
C34H60O10  +  H20,  properly  belongs  to  this  series.  But,  as  this 
analysis  had  been  made  some  sixty  years  ago,  it  seemed  imperative 
to  repeat  it  in  order  to  avoid  error.  Accordingly  a  chemical  as  well 
as  a  biological  examination  was  made  of  the  drug.  The  chemical 
examination  verified  the  correctness  of  the  formula  for  convallarin, 
*  Translated  by  Sister  Bertha  Mueller,  P.D.,  German  Hospital,  Philadel- 
phia. 
