62  Standardisation  of  Heart  Tonics.  {^ebruar'y,^™' 
mingham  physician  by  the  name  of  Withering,1  published  in  1785  the 
first  reliable  observations  of  the  medicinal  properties  of  this  drug. 
The  diuretic  properties  of  Digitalis  were  first  observed,  but  after 
the  middle  of  the  last  century  its  ability  to<  slow  the  heart  so  impressed 
the  medical  profession  that  Digitalis  was,  and  is  even  to  this  day, 
often  used  indiscriminately  for  all  conditions  where  the  heart  beat 
is  irregular  or  rapid.  It  can  now  be  demonstrated  that  Digitalis  is 
only  of  particular  value  in  a  very  limited  number  of  diseases  of  the 
heart  and  mainly  in  auricular  fibrillation. 
So  far  as  showing  the  rate  of  the  heart  beats  is  concerned,  it  may 
be  laid  down  as  a  law,  that  Digitalis  is  far  less  effective  when  the 
rhythm  of  the  heart  is  normal  than  when  there  is  auricular  fibrillation.2 
Most  authors  state  that  digitalis  causes  constriction  of  the  blood- 
vessels and  consequently  a  rise  in  blood-pressure,  yet  I  have  not  been 
able  to  demonstrate  more  than  slight  variations  in  blood-pressure  in 
test  animals,  although  various  lots  of  tinctures,  fluid  extracts  and 
proprietary  preparations  have  been  tried. 
Mackenzie  3  has  made  numerous  observations  on  various  classes 
of  patients  and  refutes  the  idea  that  the  administration  of  Digitalis 
has  a  tendency  to  produce  fatal  syncope,  provided  the  drug  is  stopped 
as  soon  as  nausea  and  vomiting  appear  or  when  the  heart  rate  falls 
below  50  per  minute. 
When  the  rhythm  of  the  heart  is  normal  the  first  symptom  is  loss 
of  appetite,  if  drug  is  continued,  vomiting,  feeling  of  malaise,  head- 
ache, and  very  little  diarrhoea  may  be  reported. 
Famulener  and  Lyons  5  state  that  the  digitalis  glucosides  act  not 
only  on  the  heart  but  directly  on  the  central  nervous  system,  first 
stimulating  then  depressing  it.  Cushny  6  states  that  "  the  chief  thera- 
peutic use  is  to  counteract  certain  changes  in  the  circulation,  which 
result  in  the  blood  accumulating  in  the  veins  in  too  large  quantities 
while  the  arteries  are  less  filled  than  usual.  In  cases  of  dilation  of 
the  heart  with  a  weak  and  insufficient  systole,  its  action  is  almost 
specific. 
"  In  these  cases  the  action  is  very  simple — the  increased  ventricu- 
lar systole  approaches  the  normal,  the  output  of  the  heart  is  increased, 
and  in  some  cases  the  dilation  is  diminished  by  the  direct  action  of 
the  drug.  The  effect  is  an  increased  velocity  and  pressure  in  the 
arteries  and  improved  nutrition  of  the  whole  body." 
There  is  no  doubt  that  Digitalis  relieves  distress  and  dropsy  and 
has  been  directly  responsible  for  numerous  cures,  yet  it  is  possible 
