m'Mav,^9Pi3arm'}       Keeping  Properties  of  Digitalis.  205 
digitalis,  when  concentrated  by  6.6  per  cent,  (sic!)  by  heat  on  a 
water  bath,  deteriorated  to  such  an  extent  that  it  required  sixty 
times  as  much  after  concentration  as  before  to  yield  its  toxic  dose. 
Hale  4  cites  the  observations  of  others  on  the  question  of  deter- 
ioration, and  remarks  that  it  would  seem  to  be  fairly  well  estab- 
lished that  the  leaves  should  be  dried  quickly  and  carefully,  and  be 
properly  stored  so  as  not  to  become  moist.  Hale  thus  accepts 
Foeke's  views,  at  least  to<  a  certain  extent.  He  does  not  believe, 
however,  that  it  is  necessary  to  reduce  the  moisture  in  the  leaves 
to  as  low  as  1.5  per  cent.,  as  suggested  by  Focke,  and  maintained 
by  certain  manufacturers  who*  prepare  a  specialty  along  these  lines. 
Hale  reports  that  leaves  which  had  been  stored  for  eight  years  in  a 
paper  bag,  and  which  contained  9.1  per  cent,  of  moisture,  gave  a 
titre  of  750  mg.  per  kilo  of  frog  by  the  one  hour  method.  Another 
sample  which  had  been  stored  in  a  cloth  bag  for  three  years,  and 
which  contained  5.8  per  cent,  of  moisture,  required  only  500  mg. 
to  kill  a  kilo  frog.  A  third  specimen  required  550  mg.  per  kilo-  of 
frog,  although  it  contained  7.8  per  cent,  of  moisture  and  had  been 
kept  in  a  paper  bag  for  two  years.  Leaves  kept  in  a  cloth  bag  for  a 
year,  and  having  a  moisture  content  of  9.4  per  cent.,  also  gave  a 
frog  titre  of  500  mg.  per  kilo.  By  way  of  comparison,  it  may  be 
stated  that  a  fresh  specimen  of  select  English  leaves,  having  7.3 
per  cent,  of  moisture,  showed  700  mg.  per  kilo  of  frog  as  its  titre, 
thus :  three  of  the  old  samples  showed  an  activity  greater  than 
that  of  the  fresh,  high  grade,  sample  of  English  leaves.  The  fourth 
showed  an  activity  about  equal  to  that  of  the  fresh  English  leaf, 
though  it  had  been  kept  in  a  paper  bag  for  eight  years,  and  in  spite 
of  the  fact  that  it  contained  9.1  per  cent,  of  moisture. 
Hale  found  that  a  sample  of  mouldy  leaves  showed  a  deteriora- 
tion of  about  90  per  cent,  in  one  year,  and  he  cites  Focke  as  having 
found  that  a  specimen  which  gave  a  valor  of  4.36  showed  a  valor  of 
only  1.6  a  year  later,  having  become  mouldy  in  the  interim.  It 
would  be  a  useless  waste  of  time  to  consider  these  mouldy  specimens 
further,  for,  of  course,  they  should  never  be  used  in  any  case. 
Several  observers  have  contended  that  heat  caused  deterioration 
in  digitalis.  Some  of  these  are  cited  by  Hale,  who  then  gives  some 
of  his  own  observations  which  tend  to  show  that  temperatures  below 
1200  C.  maintained  for  a  moderate  length  of  time  do  not  affect  com- 
*Hygien.  Lab.  Bull.  No.  74,  191 1. 
