  In liquid helium 4, many features associated to Bose statistics have been
masked by the strongly interacting nature of the liquid. As an example of these
features, we examine the shear viscosity of liquid helium 4 above the lambda
point. Applying the linear-response theory to Poiseuille's formula for the
capillary flow, the reciprocal of the shear viscosity coefficient is considered
as a transport coefficient.
  Using the Kramers-Kronig relation, we relate a superfluid flow in a capillary
with that in a rotating bucket, and express the reciprocal of the shear
viscosity coefficient in terms of the susceptibility of the system. A formula
for the kinematic shear viscosity is obtained which describes the influence of
Bose statistics. Using this formula, we study the gradual fall of the kinematic
shear viscosity from 3.7K to the lambda point in liquid helium 4 at 1 atm.
