5«4 
Relative  Activity  of  Digitalis. 
|  Am.  Jour.  Pharm. 
August,  1 918. 
about  four  per  cent.  This  increase  of  activity,  however,  was  not 
detected  by  the  guinea-pig  test. 
The  presence  of  only  a  small  amount  of  the  active  principles  of 
digitalis  in  the  petioles  should  be  of  special  interest  to  students  of 
phyto-chemistry  and  plant  physiology.  The  tissue  of  the  petiole  is 
chiefly  parenchymatous  and  deficient  in  the  essential  elements  of 
photosynthetic  activity.  On  the  other  hand,  the  lamina  portion  of 
the  leaf  is  composed  primarily  of  cells  which  are  rich  in  plastid  ele- 
ments, and  it  is  here  that  the  glucosides  of  digitalis  are  most  abun- 
dant. These  observations  would  indicate  that  the  formation  of  the 
glucosides  of  digitalis  is  closely  associated  with  photosynthetic  ac- 
tivity in  the  leaf.  From  work  now  in  progress  we  hope  to  soon 
present  data  concerning  the  time  in  the  growth  of  the  plant  when  the 
glucosides  of  digitalis  first  make  their  appearance. 
Table  III  is  especially  interesting  in  that  it  shows  that  the  num- 
ber 50  dirt  siftings  which  previously  had  given  a  negative  chemical 
reaction  for  digitalis  glucosides  possessed  marked  physiologic  prop- 
erties. The  M.  L.  D.  was  200  milligrammes  of  siftings  per  250 
gramme  body  weight  of  pig.  The  siftings  therefore  were  only  about 
one  fourth  as  active  as  the  cleaned  drug  or  about  one  half  as  active 
as  the  standard.  Post-mortem  examinations  revealed  the  hearts  to 
be  systolic.  The  animals  were  under  more  or  less  constant  observa- 
tion during  the  period  of  the  test  and  exhibited  symptoms  which 
were  not  characteristic  of  digitalis.  There  was  the  usual  loss  of 
muscular  coordination,  but  this  was  accompanied  by  frequent  spasms 
of  superexcitation.  The  spasms  were  rapid  clonic  and  began  in 
cases  of  the  pigs  receiving  the  larger  doses  shortly  after  the  admin- 
istration of  the  drug.  Opisthotonos  was  pronounced  shortly  after 
the  spasms  began.  The  rapid  contractions  and  relaxations  of  the 
extremities  continued  at  intervals,  although  the  back  remained  in 
the  arched  position  until  death.  Chemical  and  physiological  ex- 
aminations having  demonstrated  the  presence  of  only  a  small  amount 
of  digitalis  glucosides  in  the  dirt  siftings,  it  is  logical  to  assume  that 
the  unusual  symptoms  manifest  were  due  either  to  (a)  water-sol- 
uble constituents  of  the  hairs  of  digitalis  which  were  present  in  the 
siftings  in  large  numbers,  or  (b)  physiologically  active  principles  of 
the  foreign  matter  present,  or  (c)  a  possible  combination  of  effects. 
In  any  event  it  seems  to  us  that  these  observations  afford  a  strong 
argument  for  a  more  stringent  requirement  for  the  careful  garbling 
and  thorough  cleaning  of  digitalis  leaves. 
