Digitalis  Thapsi  Lin.  i<ji 
PHARMACOLOGIC  ACTION. 
By  Herbert  C.  Hamilton. 
A  preliminary  investigation  of  Digitalis  Thapsi  to  determine 
whether  it  possessed  any  of  the  therapeutic  properties  of  the  official 
drug  was  carried  out  on  frogs  by  the  M.  L.  D.  method  for  stand- 
ardization.1 The  drug  in  tincture  form  was  properly  diluted  and 
injected  into  frogs  in  gradually  decreasing  doses  until  the  minimum 
was  found  which  was  sufficiently  toxic  to  kill. 
This  dose  was  just  one  third  that  of  a  similar  tincture  from  an 
average  sample  of  official  drug  as  shown  below.  Data  of  final  tests 
only  are  here  recorded. 
Standard  Tr.  Digitalis. 
Wt.  of  frog.  Dose  per  gm.  Total  dose. 
20  009  18  alive 
20   010  20  dead 
19   010  19  dead 
21   on  23  dead 
22   on  23  dead 
Tincture  from  Thapsi  Drug. 
18   0025  23  alive 
20   0030  30  alive 
20   0035  35  dead 
21   0040  42  dead 
22   0045  49  dead 
Dilution  1  in  5. 
The  above  are  the  final  tests  showing  the  comparative  toxicities 
as  determined  by  the  minimum  lethal  doses  of  the  two  tinctures 
which  are : 
Standard  Tinct.  Digitalis    0.010 
Tinct.  Digitalis  Thapsi    0.0035 
That  the  drug  belongs  to  the  digitalis  series  of  heart  tonics  is 
shown  by  the  fact  that  in  every  case  the  heart  was  found  to  have 
stopped  in  systole,  i.  e.,  with  the  apex  of  the  heart  strongly  con- 
tracted. 
A  qualitative  test  further  to  confirm  the  action  of  the  drug  was 
made  by  dropping  the  diluted  tinctures  on  the  laid-bare  frog's  heart. 
The  two  tinctures  were  compared  as  before. 
1  Houghton  and  Hamilton,  Amer.  Jour,  of  Pharm.,  October,  1909. 
Am.  Jour.  Pharm.  \ 
April,  19 1 7.  * 
