A^ctJo°bUerr,  i9i™'}  Cardiac  Stimulants  and  Depressants.  459 
receiving  the  larger  doses  will  die,  while  the  third  will  recover. 
This  being  the  case  the  drug  or  preparation  may  be  passed  as  it 
is.  If  only  the  pig  receiving  11/i0  dies,  the  preparation  is  to  be 
concentrated  10  per  cent.  If  all  three  pigs  die,  a  fresh  pig  is  given 
V10  of  the  standard  dose  and  the  dose  is  reduced  by  tenths  until 
a  pig  lives.  The  preparation  is  then  diluted  accordingly.  If  all 
three  pigs  live,  a  fresh  pig  is  given  12/10,  and  others  increasing 
doses  until  two  die.  The  preparation  is  then  concentrated  to 
agree  with  the  smallest  amount  received  by  a  pig  which  is  killed. 
By  this  method  it  is  possible  to  make  preparations  which  are 
always  within  10  per  cent,  of  the  same  strength.  The  standards 
on  which  I  have  decided,  after  a  large  amount  of  work  with 
preparations  from  different  houses,  are  as  follows : 
Dose  Based  on  a  250  Gramme  Guinea  Pig,  and  Proportioned  to  Weight 
if  the  Pig  Used  Does  Not  Weigh  This. 
Drug  Fluidextract  Tincture  Extract 
Apocynum    0.075  c.c.         0.75  c.c. 
Convallaria    0.075  c.c.  0.75  c.c. 
Digitalis    0.1    c.c.  1.0  c.c.         0.025  Gm. 
1890 
0.25  c.c. 
0.75  c.c. 
1900 
0,5  c.c. 
Strophanthus  0.0025  c.c.        0.025  c.c. 
The  most  interesting  point  in  connection  with  this  table  is  the 
peculiar  difference  in  the  activity  of  the  three  preparations  of 
squill.  The  alcoholic  extract  is  about  twice  as  strong  as  the  acetic, 
or  a  little  more,  and  the  tincture  about  three  times  as  active  as 
the  alcoholic  extract,  in  proportion  to  drug  strength. 
We  now  turn  to  the  consideration  of  the  heart  depressants. 
There  are  only  three  vegetable  drugs  in  the  Pharmacopoeia  whose 
most  important  physiologic  action  is  a  direct  depression  of  the 
cardiac  activity, — these  being  aconite,  gelsemium,  and  veratrum. 
Related  to  these  in  action  is  a  group  of  drugs  which  exert  their 
most  marked  action  on  the  voluntary  muscles,  causing  loss  of  tone 
in  these,  and  killing  by  respiratory,  rather  than  cardiac,  failure. 
This  group  includes  physostigma,  lobelia,  and  conium.  The  drugs 
of  the  digitalis  series,  which  kill  by  depression  resulting  from  over- 
Squill. 
