I have tried to trace the history of the development of our knowledge regarding the structure and function
of the many different parts belonging to the lymphatic
system from the beginning of our knowledge of them up to the
present day. The object in taking the different parts
separately has been to show the progress more clearly and
also to impress upon one the great change which takes place
when one theory supplants another. How, when there is doubt
about the function and structure of an organ or part, there
generally follows a host of different theories. Take for
example that theory of Hunter's which had caused the
opposing theory of venous absorption to fall into the shade.
It was almost decided by all to be correct - and then at the sound of Magendie the scales were changed.
In a more gradual way it has been interesting to
notice how the mechanical theory of absorption has given
way to the vital theory. It is owing partly to the parallel
progress made in our knowledge of the other parts and
functions of the body that we to -day have built up
the knowledge we have regarding the structure and functions
of the lymphatic system.