Dialysis blocks the passage of larger substances (for example, red blood cells, large proteins). This replicates the filtering process that takes place in the kidneys when the blood enters the kidneys and the larger substances are separated from the smaller ones in the glomerulus. The two main types of dialysis, hemodialysis and peritoneal dialysis, remove wastes and excess water from the blood in different ways. Hemodialysis removes wastes and water by circulating blood outside the body through an external filter, called a dialyzer, that contains a semipermeable membrane. The blood flows in one direction and the dialysate flows in the opposite.
Water organ power the restored six-stop instrument. Among Renaissance writers on the water organ, Salomon de Caus was particularly informative. His book of 1615 includes a short treatise on making water organs, advice on tuning and registration, and many fine engravings showing the instruments, their mechanisms and scenes in which they were used. It also includes an example of suitable music for water organ, the madrigal Chi farà fed' al cielo by Alessandro Striggio, arranged by Peter Philips. Water organs were described in the numerous writings of the famous Ctesibius (3rd century BC), Philo of Byzantium (3rd century BC) and Hero of