Am.  Jour.  Pharm.  ) 
July,  1915.  I 
Disinfection. 
321 
sentation  of  the  comparative  efficiencies  and  toxicities  of  representa- 
tives of  the  three  groups.  The  '*  1  Vol."  square  is  shown  in  the  lower 
right-hand  corner,  while  the  four  larger  squares  show  the  volumes  to 
which  this  one  volume  of  phenol  and  of  each  of  the  three  groups  can 
be  diluted,  all  of  the  dilutions  having  the  same  germicidal  efficiency — 
a  phenol  coefficient  of  0.04. 
Hj     Toxicity  33% 
Group  3  -  Sigh  Coefficient  Disinfectants 
Dilution  1 
Vol.  to  500 
Coefficient  of  Dilution 
0.04 
■ 
Toxicity  2Z% 
Group  2 
-  Coal  Tar  Disinfectant 
Ordinary  type 
s 
Dilution  1  Vol.  tol60 
Coefficient  of  Dilution 
0.04 
■ 
Toxicity  4=5%     Group  1 
Cresylic  Acid  Scan  Solution 
Dilution  1  Vol",  to  50 
Coeff. 
of 
gj  Toxicity  100$ 
Dil. 
0.04 
PHS1I0L 
1  Vol.  to 
£5 
Coeff.  of  Dilution 
0.04 
1 
Vol 
The  toxicities  are  shown  graphically  by  the  square  in  the  upper 
left-hand  corners  of  the  four  squares  representing  the  dilutions. 
Phenol,  being  used  as  a  standard,  is  entirely  black,  while  the  others 
are  blackened  in  proportion  to  their  toxicities,  expressed  in  per  cent, 
of  that  of  phenol.  The  ratio  of  the  black  "  toxicity  "  square  is  a 
graphic  representation  of  the  non-toxic  character  of  these  dilutions 
compared  to  that  of  phenol.  For  example,  Group  3  with  a  toxicity 
of  thirty-three  per  cent,  has  a  black  square  one-third  as  large  as  that 
