AmMayriw5arm"}  Remarks  on  Digitalis.  217 
saponin.  He  therefore  supposes  that  no  change  takes  place  when  the 
infusion  cools,  although  every  druggist  knows  that  a  slight  pre- 
cipitate forms,  and  he  also  must  suppose  that  this  saponin  and  the 
insoluble  digitoxin  are  present  always  in  the  right  proportion, — that 
is,  enough  saponin  to  dissolve  the  digitoxin.  As  a  matter  of  fact, 
however,  the  presence  of  saponin  is  still  in  doubt,  and  even  those  who 
claim  its  presence  do  not  agree  on  the  quantity,  some  speaking  of  a 
trace  only.  But  nearly  all  investigators  agree  on  the  instability  of  the 
various  digitalis  preparations  and  the  ease  with  which  the  one  is 
changed  into  the  other.  Some  doubt  the  presence  of  any  preexist- 
ing digitoxin  in  the  plant,  believing  that  it  forms,  after  the  leaves  are 
gathered,  through  the  influence  of  this  saponin.  We  are  reminded 
of  bitter  almonds,  where  the  amygdalin,  through  the  action  of  a  fer- 
ment, is  changed  into  benzaldehyde,  hydrocyanic  acid  and  glucose. 
Might  there  not  be  a  similar  cause  in  digitalis  that  would  account 
for  the  evasiveness  of  the  various  chemicals?  It  cannot  be  doubted 
that  a  soil  containing  iron  and  manganese  is  most  favorable  to  the 
development  of  the  plant,  and,  if  the  claim  that  manganese  is  nec- 
essary for  the  production  of  digitoxin  is  correct,  what  hinders  us 
to  suspect  a  certain  relationship  between  manganese  and  this  com- 
plex body?  To  the  adherer  of  the  infallibility  of  the  theory  of 
elements  such  a  thought  may  appear  like  the  outgrowth  of  a  dis- 
ordered imagination.  But  other  apparently  impossible  theories  have 
been  proved  to  be  founded  on  facts,  and  a  chemical  genius  may  come 
some  day  and  upset  many  of  our  pet  theories.  The  inadequacy  of 
the  chemistry  of  digitalis  should  certainly  lead  the  investigators  to 
consider  the  plant  as  a  harmonious  total,  and  not  take  out  its  chem- 
istry as  a  part  that  can  be  studied  and  understood  without  reference 
to  its  whole  life  and  development  and  productions. 
It  would  be  wrong  to  write  a  review  of  digitalis  without  men- 
tioning the  physiological  tests  to  which  this  plant  has  been  subjected 
in  the  last  two  decades.  Here  the  same  confusion  reigns  as  in  its 
chemistry.  Naturally  so.  How  can  we  successfully  test  a  chemical 
before  we  have  absolute  knowledge  of  its  properties?  Frogs,  mice, 
rabbits,  dogs,  cats,  have  been  used  to  establish  what  is  called  a 
standard.  But  no  two  investigators  agree.  These  physiological 
tests  are  beyond  the  scope  of  the  pharmacist  and  physician,  as  they 
require  especially-arranged  biological  laboratories  that  cannot  be 
established  without  considerable  expense.  In  the  same  way  the 
physiological  chemist  requires  special  training  and  long  experience. 
