Reviewing studies on lymphatics in retrospect， there have been two streams of studies
through the present time: One originated in the 17th century; and the other developed
centering on the studies in the 19th century. Since 1923， however， there arose a third
boom of new researches which have continued to the present.
The author， together with many collaborators reviewed the investigations and discoveries
of our predecessors in this field and confirmed them one by one using the latest methods.
Adding our own 五nding to the earlier work， we arrived at the following conclusion:
The lymphatic system along with the venous sytem， regulates return flow of body fluid
to the heart by passive and active contractility and valve action， and by means of its wall
extensibility as a body fluid reservoir. 10 future， oot ooly the control mechaoism of body
fluid circulation among the heart， blood vessel system aod lymphatic system but also body
fluid flow in tissue spaces must be studied.