The  ALVEOLAR  EPITHELIAL  CELLS  are  important  because  of  their
considerable  number  in  nearly  every  sputum  examined,  even  of  normal
persons,  since  they  are  desquamated  as  from  all  epithelial  surfaces;  and
because  of  the  large  variety  of  forms  which  they  may  assume,  some  of
which  it  is  very  difficult  to  recognize.  Every  observer  is  pretty  certain
to  be  deceived  once  or  oftener  by  these  cells.  In  general,  they  may  be
said  to  be  from  four  to  five  times  the  size  of  a  leucocyte,  oval,  with  a
coarsely  granular  protoplasm  and  one  or  more  large,  oval,  vesicular
nuclei.  They  are  found  in  normal  sputa,  as  well  as  in  almost  every
other  condition.  Their  large  number  in  bronchitis  would  indicate  some
intimate  pathological  relation  between  the  bronchi  and  the  alveoli.
They  are  most  numerous  in  inflammatory  processes  of  the  lung,  and
especially  in  tuberculosis,  w^here  they  may  fill  the  alveoli,  although
retained  here  and  hence  do  not  appear  in  the  sputum.  These  cells  are
•Miinch.  med.  Wochnschr.,  igo/^,  No.  3.
