Bacilli  may  pass  from  Stomach  to  Lungs.  —  It  is  com-
monly assumed  that  because  pulmonary  tuberculosis  begins
in  the  apices  of  the  lungs  the  bacilli  must  be  carried  directly
to  the  alveoli  by  the  inspired  air.  Moreover  most  patholo-
gists  consider  that  evidence  points  to  the  alveolar  surface  as
the  starting  point  of  the  disease,  and  that  the  relative  age  of
the  lesions  in  the  lungs  and  the  glands  indicates  that  it  is
primarily  a  pulmonary  disease.  The  writer  is  not  competent
to  discuss  the  findings  of  the  pathologists,  but  there  are  a
large  number  of  careful  observers  who  believe  on  pathological
and  experimental  evidence  that  the  bacilli  which  cause  pul-
monary tuberculosis  may  find  their  way  through  the  lymph
and  the  blood  from  any  part  of  the  alimentary  tract  to  the
lungs.  Some  pathologists  believe  that  the  disease  begins
in  the  capillaries  rather  than  in  the  alveoli.  Calmette  and

1  VallSe,  Ann.  d.  Tlnst.  Pasteur,  1905,  XIX,  619.
2  Calmette  and  Guerin,  Ann.  de  1'Inst.  Pasteur,  1905,  XIX,  601.
3  Weleminsky,  Berl.  klin,  Wchnschr.,  1905,  XLII,  743.
306      THE  SOURCES  AND  MODES  OF  INFECTION

Guerin  1  say  that  primary  tubercle  of  the  lungs  always  be-
gins in  the  capillaries,  and  never  in  the  alveoli,  and  Aufrecht 2
from  his  pathological  studies  comes  to  the  same  conclusion.
Even  pulmonary  anthracosis  may  be  caused  by  the  inges-
tion  of  particles  of  carbon.  Vansteenburgh  and  Grysez 3
caused  animals  to  breath  air  loaded  with  soot  from  a  smoky
lamp,  and  though  the  nose  was  filled  with  soot,  none  was  found
in  lungs  or  even  trachea.  If  the  experiment  was  prolonged,
carbon  appeared  in  the  lungs,  but  not  if  the  esophagus  was  tied.
