Am.  Jour.  Tharm. 
June,  1913. 
Disinfectants  and  Algicides. 
247 
acids  suggested  that  the  juice  of  this  berry  could  be  used  as  an 
indicator  in  volumetric  analysis. 
Employing  a  few  drops  of  the  neutralized  juice,  I  find  that 
the  color  reaction  is  very  delicate,  changing  from  an  olive-green  in 
alkaline  solution  to  the  rose  color  in  acid  solution.  Volumetric 
solutions,  ranging  from  N/i  to  N/50,  were  tried  and  the  color 
change  was  found  sensitive  to  one  drop  of  the  latter  solution. 
The  extent  of  the  present  investigation  seems  to  indicate  that 
the  action  is  similar  to  that  of  Litmus.  This  is  especially  true 
concerning  its  behavior  with  carbonates.  It  is  sensitive  to  carbonic 
acid  and,  as  in  the  case  of  litmus,  the  solution  of  carbonate  must 
be  boiled. 
In  common  alkaloidal  work,  the  titration  of  excess  N/10  acid  by 
means  of  N/50  alkali,  the  new  indicator  was  found  to  not  only 
equal  cochineal  in  sensitiveness  but  to  have  the  advantage  of  a 
more  decided  change  in  color. 
Drug  Laboratory, 
University  of  Kansas. 
THE  RATIONAL  USE  OF  DISINFECTANTS  AND  ALGI- 
CIDES IN  MUNICIPAL  WATER  SUPPLIES.1  - 
By  Karl  F.  Kellerman,  Washington,  D.  C. 
Most  cities  must  secure  their  water  supplies  from  polluted 
sources;  it  is  useless  to  attempt  a  close  imitation  of  natural  proc- 
esses in  purifying  this  water. 
The  responsibility  for  purifying  water  rests  upon  the  company 
or  municipality  which  supplies  it  to  the  consumers,  but  there  should 
be  authority  for  preventing  unreasonable  pollution  by  one  com- 
munity of  the  sources  of  supply  of  other  communities. 
Disinfection  of  a  water  by  chemical  agents  is  desirable  as  an 
emergency  treatment  in  case  of  temporary  pollution  of  a  supply; 
it  is  desirable  as  a  routine  method  in  case  the  supply  is  continuously 
subjected  to  dangerous  pollution. 
Hypochlorite  is  at  present  the  cheapest  as  well  as  the  most 
efficient  agent  for  the  disinfection  of  water. 
1  Abstract  of  paper  presented  before  Section  VIII  on  Hygiene,  at  the 
Eighth  International  Congress  of  Applied  Chemistry,  Washington  and  New- 
York,  September  4-13,  1912,  and  reprinted  from  "  Wasser  und  Abwasser," 
Band  6,  1913. 
