Quotation from: Manual of Surgery

Written by: Alexander Miles and Alexis Thomson

An _unhealthy or devitalised condition of the patient's tissues_ also
hinders the reparative process. Bruised or lacerated skin heals less
kindly than skin cut with a smooth, sharp instrument; and persistent
venous congestion of a part, such as occurs, for example, in the leg
when the veins are varicose, by preventing the access of healthy blood,
tends to delay the healing of open wounds. The existence of grave
constitutional disease, such as Bright's disease, diabetes, syphilis,
scurvy, or alcoholism, also impedes healing.