Animals that are internally and externally viviparous are more
abundantly supplied with blood than the sanguineous ovipara. Animals
that are in good condition, either from natural causes or from their
health having been attended to, have the blood neither too abundant-as
creatures just after drinking have the liquid inside them in
abundance-nor again very scanty, as is the case with animals when
exceedingly fat. For animals in this condition have pure blood, but
very little of it, and the fatter an animal gets the less becomes
its supply of blood; for whatsoever is fat is destitute of blood.