662 
The  Pollution  of  Water. 
5  Am.  Jour.  Pharm. 
I     Sept..  1921. 
organisms  of  infectious  disease  and  thus  represent  a  potential  men- 
ace to  those  who  drink  water  or  eat  food  that  have  been  contami- 
nated by  it.  But  domestic  sewage  ordinarily  contains  nothing  detri- 
mental to  the  growth  of  the  aquatic  organisms  which  help  to  com- 
plete the  disintegration  of  the  excreta  and  which  thrive  on  it.  Sew- 
age, indeed,  supplies  a  source  of  plant  and  animal  nutriment  in  the 
water  as  truly  as  on  the  soil.  Nelson  reminds  us  that  under  favora- 
ble conditions  a  small  stream  may  dispose  of  the  sewage  of  a  rela- 
tively large  population,  and  the  stream  in  turn  be  supplied  with  a 
constant  source  of  animal  and  plant  nutriment.  There  is  a  true  fer- 
tilizing action  on  the  water,  with  a  resultant  large  increase  in  the 
number  of  the  organisms  present.  Since  fish  and  shellfish  utilize 
these  plant  and  animal  organisms  as  food,  it  follows  that  the  ad- 
dition of  domestic  sewage  to  a  body  of  water  will  result  ultimately 
in  an  increase  in  the  amount  of  human  food,  in  the  form  of  fish 
and  shellfish  derived  from  it,  as  truly  as  though  the  sewage  were 
employed  in  fertilizing  land  crops.  The  danger  of  eating  shellfish 
removed-  from  grossly  polluted  water  thus  lies  in  the  presence  of 
pathogenic  bacteria,  rather  than  in  the  inert  organic  matter  present 
in  the  medium.  The  problem  of  purification  of  such  products  as 
oysters  primarily  becomes  one  of  sanitary  bacteriology.  It  can  be 
met  by  avoiding  the  pollutions;  or,  if  this  is  not  entirely  feasible, 
the  food  can  still  be  conserved  by  disinfection  procedures.  But  of 
late  the  oyster  itself  is  becoming  threatened  with  extinction  because 
of  an  added  kind  of  contamination  represented  by  the  great  indus- 
tries which  discharge  effluents  into  the  streams  reaching  the  coast. 
Oils,  acids  and  alkalis,  metallic  poisons  and  other  chemical  com- 
pounds may  interfere  with  all  forms  of  life,  whether  micro-organ- 
isms which  themselves  aid  in  the  self-purification  of  our  natural 
waters,  or  the  animals  and  plants  which  normally  thrive  and  de- 
velop in  them.  In  other  words,  the  disposal  of  industrial  wastes  has 
complicated  the  disposal  of  human  waste,  and  incidentally  an  im- 
portant source  of  delectable  human  food  is  likely  to  be  impaired. 
Something  remedial  must  be  done,  and  soon. 
