432  Stability  of  Digitalis  Leaf  Extracts.  {Am'j{^yr' 
Date. 
M.  S.  D.,  Mils. 
Toxicity,  Per  Cent. 
Period  in  Months. 
Feb.  9,  1918  ,  
0.0055 
110. 0 
July  27,  1918  
O.OIO 
60.0 
5 
Aug.  31,  1918  
O.OII 
54-0 
6 
Sept.  26,  1918  
0.0141 
42  5 
7 
Oct.  20,  1918  
0.0141 
42.5 
8 
Nov.  17,  1918  
0.0141 
■  42.5 
9 
April  1,  1919  
0.0141 
42.5 
14 
Tincture  5.  No.  39220  (D-1625)  6-21-18.  Alcohol  64  per 
cent. 
Date. 
M.  S.  D.,  Mils. 
Toxicity,  Per  Cent. 
Period  in  Months. 
June  29,  1918  
0.0066 
90 
July  27,  1918  
0.0071 
84 
I 
Aug.  31,  1918  
O.O0769 
78.O 
2 
Sept.  28,  1918  
O.OO774 
77-5 
3 
O.OO827 
72.5 
v-  4 
0.00827 
72.5 
5 
Feb.  23,  1919  
0.00857 
70.0 
8 
From  these  results  we  may  plot  the  rate  of  deterioration  for 
tinctures  as  recorded  by  the  one-hour  frog  method  as  follows : 
1 
if 
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or 
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T 
MC 
TU 
rto 
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(/ 
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\ 
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Ho 
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It 
5 
is 
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\ 
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1  1 
1  1 
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r 
U 
>  r 
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Fig.  I. 
