438  Specificity  of  Drugs  for  Phosphatids.    ^VltXr^™ ' 
cipitated  in  a  .0048  molecular  solution.  A  few  days  later  the  molec- 
ular concentration  required  was  .0055.  After  a  week  it  had  risen 
to  .0059  M.  If  the  state  of  oxidation  of  the  phosphatid  is  related 
to  the  nature  or  amount  of  combination  between  the  phosphatid  and 
the  drug,  one  would  expect  that  the  presence  of  the  drug  would 
affect  the  rate  of  oxidation  of  the  lipin.5  There  seems  to  be  but 
little  doubt  that  one  of  the  effects  of  those  drugs  which  give  evi- 
dence of  combining  with  the  phosphatids  is  to  alter  the  auto- 
oxidation  of  the  lipin. 
Relation  to  Drugs— -In  the  following  tables  drugs  in  a  dilution 
of  1/1000  were  used  instead  of  more  concentrated  solutions,  be- 
cause these  small  quantities  seemed  comparable  with  the  amounts 
that  might  actually  exist  in  a  tissue  when  therapeutic  amounts  are 
given. 
Table  I. 
Heart  Lecithin  A,  0.3  Per  Cent. 
-   
CaCl2  to  ppt. 
Control. 
Diff.  in  CaClo. 
1/1000  digitalis  
.0110 
.0044 
+.0066 
"  strophanthin  
.0057 
.0044 
+  .0013 
.0057 
.OO44 
+  •0013 
.0066 
.0044 
+  .0022 
saponin  
.0052 
.0044 
+  .0008 
.0044 
.0044 
.0 
.0044 
.OO44 
.0 
.0044 
.0044 
•O 
"  theobromine  
.0044 
.0044 
.0044 
.0044 
.0 
.0044 
.OO44 
.0 
.0040 
.0044 
—  .0004 
Table  II. 
Heart  Lecithin  B,  0.2  Per  Cent. 
CaClo  to  ppt. 
Control. 
Diff.  in  CaCl2. 
.0059 
.0055 
+  .0004 
.0059 
.0055 
+  .0004 
.0068 
.0059 
+  .0009 
.0068 
.0059 
+  .0009 
.0064 
•0055 
+  .0009 
.0048 
.0048 
.0 
•0055 
•0055 
.0 
.0055 
•OOS5 
.0 
.0055 
•OO55 
.0 
.0064 
.0055 
+  .0009 
.0066 
.0048 
+  .0018 
5  This  question  is  being  studied  directly  by  adding  drugs  to  phosphatid 
solutions  and  comparing  the  rate  of  oxidation  with  phosphatid  controls. 
