Countercurrent  exchange  in
   albatross salt glands.
<P>
<lI> Blood  flow  in the capillaries is counter to the flow of fluid in
the secretory tubules.
<lI> Secretory  cells  actively  transport salt from the blood into the
secretory tubules.
<P>
   The  countercurrent  flow minimizes salt concentration gradient across
   the secretory cells.
<P>
   The excess salt is secreted through ducts.