Milk-borne  typhoid  fever,  on  the  other  hand,  probably  does
occur  chiefly  in  the  form  of  outbreaks.  During  the  last  four
years,  in  Providence,  155  of  the  600  milk  dealers  have  had
one  or  more  cases  of  typhoid  fever  on  their  routes.  In  only
9  instances  have  there  been  more  than  2  cases  on  a  single
route  within  a  week.  Investigation  promptly  showed  that
in  3  instances  the  groups  of  cases  were  due  to  personal  con-
tact, and  in  the  other  6  instances  an  unmistakable  milk
outbreak  developed.  It  is  true  that  some  epidemiologists
assume  that  a  considerable  number  of  sporadic  cases  are  due
to  milk,  but  the  evidence  appears  to  be  the  other  way.  I
think  that  a  study  of  the  distribution  of  typhoid  cases  on
milk  routes  in  Washington,  as  shown  in  diagrams  in  bulletins
35,  44  and  52  of  the  Hygienic  Laboratory,  United  States
Public  Health  and  Marine  Hospital  Service,  bears  out  my
contention  that  outbreaks  of  typhoid  fever  due  to  milk  are
not  likely  to  escape  notice  if  the  cases  are  daily  tabulated
according  to  milk  supply.  Furthermore,  these  charts  show
that  there  is  little  excess  of  typhoid  fever  on  individual  milk
supplies  except  in  those  instances  where  there  is  a  noticeable
outbreak.
