A  January  m™'  \  Resistance  of  Guinea  Pigs  to  Poisonini 
SEASONAL   VARIATIONS    IN    THE    RESISTANCE  OF 
GUINEA  PIGS  TO  POISONING  BY  OUABAIN  AND  BY 
liquid'  PREPARATIONS  OF  DIGITALIS. 
By  C.  C.  Haskell,  A.B,  M.D. 
In  a  previous  paper  1  it  has  been  shown  that  guinea  pigs  are  more 
resistant  to  poisoning  by  ouabain  during  certain  months  of  the  year 
than  at  others.  These  results  were  confirmed  in  a  general  way  by 
Vanderkleed  and  Pittenger  2  in  a  subsequent  publication.  It  is  of 
interest  to  compare  the  results  secured  in  this  laboratory  with  those 
reported  by  Vanderkleed  and  Pittenger. 
I  have  used  male  pigs  exclusively,  and  have  been  compelled  to 
employ  animals  differing  largely  in  weight;  the  majority,  however, 
weighed  250  grams  or  more,  so  it  seems  best  to  compare  my  results 
with  those  obtained  by  Vanderkleed  and  Pittenger  using  "  large 
males."  In  order  to  facilitate  comparison,  the  average  minimum 
lethal  dose  has  been  expressed  in  fractions  of  a  gram  per  gram  body 
weight  and  put  in  the  following  tabular  form : 
Table  I. 
Month. 
Vanderkleed  and  Pittenger. 
Haskell. 
January  
.  1912 
.OOOOOO25 
.OOOOOO52  + 
February  
1912 
. OOOOOO30 
.OOOOOO37 
March.  
. . 1912 
.OOOOOO32 
. OOOOOO36 
April  
1912 
. OOOOOO33 
. OOOOOO4O 
May  
1912 
. OOOOOO33 
. OOOOOO45 
June  
1912 
. OOOOOO33 
. OOOOOO4O 
July  
.  .1911 
. 0000002 I 
August  
1911 
. 0000002 1 
. OOOOOO29 
September  
. . 191 1 
. 0000002 I 
. OOOOOO30 
October  
1911 
. 0000002 1 
. OOOOOO36 
November  
1911 
. OOOOOO24 
. OOOOOO52 
December  
1911 
.OOOOOO28 
.OOOOOO52 
It  is  readily  seen  that  the  same  general  conclusion  is  deducible 
from  both  series  of  tests  :  the  resistance  of  the  pigs  is  least  during  the 
hot  summer  months  and  greatest  in  the  cooler  weather.  In  August, 
there  is  a  difference  of  38  per  cent,  between  the  lethal  dose  required 
1  Am.  Jour.  Pharm.,  Vol.  84,  No.  6,  p.  241,  1912. 
2  Jour.  Am.  Ph.  Assoc.,  Vol  n,  No.  5,  P-  558,  1913- 
