The blood viscosity depends on the number of
the corpuscular elements pres e n t ?and on the viscosity
of the plasma. It is rapidly altered by conditions
which concentrate or dilute the fluid of the blood,
and is very sensitive to slight variations in the
carbon dioxide. Such changes are readily neutralised
in health, but under disease conditions persistent
alterations of the blood viscosity frequently occur.
It is probable that many of the symptoms found in
such cases, may be directly attributable to the
altered blood viscosity.
For a proper understanding of the physics of the
circulation it is essential to have a knowledge of
the part played by blood viscosity}and of the modifications it may undergo in disease.