1 66 
Use  of  Preservatives  in  Foods. 
f  Am.  Jour.  Pharncu 
I       April.  1906. 
drug,  which  lies  only  at  an  infinitely  small  distance  from  zero  to  the 
left  on  the  base  line,  but  at  the  point  75  on  the  base  line  we  are 
able  to  measure  the  effect  of  the  drug.  We  can  also  measure  it  at 
the  point  50  and  at  the  point  25,  and  having  determined  these  three 
points  construct  the  theoretical  curve.  In  the  same  way  we  cannot 
measure  the  effect  of  diminishing  the  normal  dose  of  a  food  by  an 
LETHAL  DOSE 
100- 
GRAPHIC  CHART  REPRESENTING  THE  COMPARATIVE 
INFLUENCES  OF  FOODS  AND  PRESERVATIVES. 
\ 
LETHAL  DOSE 
25 
50 
75 
NORMAL  DOSE 
•100 
r80 
60 
40 
-20 
NORMAL  DOSfc 
infinitely  small  quantity,  which  would  be  at  an  infinitely  small 
distance  from  ico  on  the  right,  in  descending  toward  the  base  line. 
We,  however,  could  measure  the  effect  of  diminishing  the  food  to 
the  extent  represented  at  the  point  80  on  the  right,  or  at  the  point 
between  40  and  30,  or  at  the  point  between  20  and  10  on  the  left,  or 
between  10  and  zero,  which  latter  point  would  be  absolute  starvation. 
Thus  it  is  wholly  illogical  and  untrue  to  state  that  a  small  dose  of  a 
harmful  substance  produces  no  effect.    It  simply  produces  no  effect 
