INFECTION  BY  CONTACT  205

Kavacs1  and  Preisich  and  Schiitz.2  Among  others  who  at-
tribute much  importance  to  contact  infection  may  be  men-
tioned Wassermann,3  Calmette  and  Landouzy.4

Certainly  the  opportunities  for  the  direct  transfer  of  fresh
moist  infective  material  in  the  home  of  a  phthisical  patient
must  be  very  great,  while  the  chance  of  the  infective  material
becoming  dried,  pulverized  and,  while  still  virulent,  being  car-
ried to  the  pulmonary  alveoli,  must  be  comparatively  small.
Unless  there  is  some  good  reason  to  think  otherwise,  one
would  naturally  attribute  to  contact  infection  the  chief  role
in  the  extension  of  this  disease,  at  least  in  the  family.  The
only  objection  is  offered  by  the  pathologists,  many  if  not
most  of  whom  affirm  that  the  evidence  points  to  direct  infec-
tion of  the  lungs  by  the  inspired  air.  There  are,  however,
many  able  experimenters  who  think  otherwise,  and  who  main-
tain that  tubercle  bacilli  may  enter  the  body  at  various  points
and  reach  the  lungs  through  the  lymph  channels.  It  is  impos-
sible for  the  writer  properly  to  weigh  pathological  evidence,
but  that  the  question  is  still  sub  judice  must  be  admitted.
