Am.  Jour.  Pharm. 
April,  19 19. 
Digitalis  Purpurea. 
219 
TABLE  V. 
Showing  the  Activity  of  Digitalis  Leaves  Dried  at  Various  Temperatures. 
Sample  No.  Conditions  of  Drying.  Activity  Per  Cent. 
1.  Out  of  door  temperature  28°  C   166 
2.  In  oven  55-600  C   142 
3.  In  oven  ioo°  C.  . . . ,   166 
4.  Heated  in  oven  at  ioo°  C.  1  hr.  then  dried  at  55-600  C   166 
5.  Heated  in  autoclave  15  lbs.  pressure  for  1  hr.  then  dried  at 
55-6o°  C   125 
That  the  conditions  of  temperature  under  which  digitalis  leaves 
are  dried  influence  their  activity  is  quite  apparent.  The  samples 
dried  in  the  oven  at  ioo°  C,  and  heated  in  the  oven  at  ioo°  C.  for 
an  hour  then  dried  at  55-600  C.  had  the  same  activity  as  that  which 
was  dried  spontaneously  at  a  temperature  of  280  C.  On  comparing 
the  results  of  the  three  above  mentioned  with  the  results  of  the 
sample  dried  at  55-60°  C,  it  is  seen  that  55-60°  C.  is  an  undesirable 
temperature,  if  the  highest  activity  is  to  be  secured.  The  explana- 
tion for  the  low  results  of  the  sample  dried  at  55-60°  C.  as  com- 
pared with  that  dried  at  100°  C,  is  that  in  the  former  case,  the 
activity  might  have  been  lost  due  to  enzyme  action  as  has  been  stated 
by  investigators,  previously  referred  to,  while  in  the  latter  case,  the 
enzyme  activity  was  stopped  at  once.  Autoclaving  at  15  pounds 
pressure  for  one  hour  then  drying  at  55  to  60°  C.  proved  too  de- 
structive, as  the  results  of  samples  treated  by  this  method  were  41 
per  cent,  less  in  activity  than  the  sample  which  was  heated  in  the 
oven  at  ioo°  C.  and  then  dried  at  55  to  60°  C. 
Summary. 
From  the  results  of  the  experiments  with  digitalis,  we  sum- 
marize as  follows : 
1.  The  ordinary  blotting  paper  method  proved  satisfactory  for 
determining  the  viability  of  digitalis  seeds. 
2.  By  the  blotting  paper  method,  using  good  viable  seed,  86  per 
cent,  germinated  in  9  days. 
3.  The  viability  of  digitalis  seed  was  variable,  -being  from  7.5 
to  91  per  cent,  viable. 
4.  When  planting  digitalis  seeds  in  soil,  most  of  the  seeds  had 
sprouted  and  were  %  of  an  inch  high  on  the  6th  day  after  planting. 
5.  The  most  economical  method  of  securing  digitalis  plants  in 
the  greenhouse,  is  to  sow  the  seed  directly  in  small  pots.  After 
