^""M^y.^m*'"'"*}         Standardisation  of  Digitalis.  207 
evidences  of  injury  and  careful  examination  of  many  sections  of 
both  hippocampus  major  and  cerebellum  gave  a  negative  result  " 
13  months  later.  Several  instances  cited,  showing  uncertainty  in 
reaction  of  guinea-pigs  to  glanders  infection.  "  Aside  from  these 
cases,  we  have  several  times  failed  to  get  a  reaction  in  the  pigs 
when  the  potato  cultures  from  the  swabs  showed  typical  colonies 
and  these  injected  into  pigs  proved  to  be  B.  mallei." 
Doubtless,  numerous  investigations  have  been  carried  out  to 
show  that  guinea-pigs  do  not  vary  in  their  resistance  to  digitalis 
intoxication,  but  I  have  been  unable  to  find  the  report  of  a  single 
series  of  experiments  performed  with  the  object  of  showing  that 
guinea-pigs  are  not  fully  as  much  influenced  by  adventitious  cir- 
cumstances as  are  frogs.  On  the  other  hand,  Houghton  states 
that  he  found  guinea-pigs  unsatisfactory  as  compared  to  frogs  and 
Gley  ^  mentions  variability  of  the  animals  depending  upon  weight, 
and,  as  most  important  cause,  the  "  physiologic  factor,"  the  degree 
of  organic  resistance,  due  to  individual  peculiarities.  In  view  of 
these  statements  and  the  rather  suggestive  results  of  Arms,  it  would 
seem  advisable  to  make  such  a  report  before  advocating  the  use 
of  guinea-pigs  to  the  exclusion  of  other  animals. 
The  Philadelphia  committee  state  that  Edmunds  and  Hale 
found  that  only  three-fourths  of  the  dose  necessary  to  cause  systohc 
stoppage  of  the  frog's  heart  within  an  hour  was  needed  to  kill  the 
animal  in  12  hours.  In  the  bulletin  containing  the  report  of 
Edmunds  and  Hale,^  the  results  secured  by  each  of  the  frog 
methods  is  summarized.  Comparing  these  results  in  tabular  form, 
we  have: 
M.L.D. 
in  12  hours. 
I  hour  method. 
Preparation 
cc 
mgms. 
cc  mgms. 
B.  W.  &  Co. 
0.015 
1-5 
0.020  2.0 
Mulford  No.  2 
0.020 
2.0 
0.016  1.6 
S.  &  D.  • 
0.027 
2.7 
0.027  2.7 
P.  D.  &  Co. 
0.029 
2.9 
0.021  2.1 
It  is  seen  that  only  in  one  instance  was  the  dose  determined  by 
the  12-hour  method  smaller  than  that  determined  by  the  one-hour 
method.  I  shall  endeavor  to  point  out  later  that  these  methods 
are  not  similar  and  we  should  not  expect  the  same  results.  One 
advantage  possessed  by  the  one-hour  method  is  that  the  lymph  sac 
is  opened  preparatory  to  exposing  the  heart  and  any  unabsorbed 
drug  is  discovered,  enabling  us  to  disregard  that  animal,  an  ad- 
