If  the  sputum  be  squeezed  out  between  two  plates,  these  small  frag-
ments can  be  seen  as  yellowish,  often  pigmented  threads,  for  the  most
part  just  on  the  limit  of  vision  while  some  are  even  2  cm.  long;   or


THE   SPUTUM  23

as  masses  from  those  very  minute  to  those  the  size  of  a  pea.  The
search  is  much  facilitated  by  a  small  hand-lens.  They  are  found  in
the  greatest  numbers  in  the  nummular  masses  from  a  tuberculous
cavity.  Necrotic  fragments  of  cartilage  from  tuberculous  ulcers  of
larynx,  trachea,  or  bronchi  are  sometimes  found.  Tumor  fragments
should  be  looked  for.
Dittrich's  plugs  are  bodies  of  considerable  interest.  They  are
sausage-shaped  casts  of  bronchi,  varying  in  size  from  very  small  to
those  the  size  of  a  bean,  but  the  majority  from  that  of  a  millet-  to  a
mustard-seed.  The  smaller  are  of  an  opaque  yellowish-white,  the
larger  of  a  dirty  gray  color.  If  crushed  between  the  fingers  they  are
found  to  have  a  horrible  stinking  odor.  Microscopically,  they  consist
for  the  most  part  of  zooglia  of  bacteria,  fatty  acid  crystals,  fat  droplets,
and  cell  detritus.  Few  cells  are  contained,  except  in  some  a  few  leuco-
cytes indicating  perhaps  that  the  plug  is  fresh.  Pigment  granules,
fragmented  red  corpuscles,  haematoidin  crystals,  flagellates,  and  a  lep-
tothrix  taking  a  fine  blue  with  iodine  solution  and  not  yet  well  studied,
have  been  found.  The  fatty  acid  crystals  of  the  larger  plugs  are  long
and  curv^ed,  while  those  of  the  shorter  are  fine  needles.  These  plugs
occtir  in  any  putrid  disease,  especially  putrid  bronchitis  and  bronchiec-
tasis, in  which  case  they  are  especially  large.  How  these  are  formed  we
do  not  know  ( Hoffmann ) .  Similar  plugs  are  derived  from  the  crypts
of  the  normal  tonsils,  and  especially  in  case  of  follicular  tonsillitis.
