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 Western Europe. During the Renaissance, water organs again acquired magical and metaphysical connotations among followers of the hermetic and esoteric sciences. Organs were placed in gardens, grottoes and conservatories of royal palaces and the mansions of rich patricians to delight onlookers not only with music but also with displays of automata – dancing figurines, wing-flapping birds and hammering cyclopes – all operated by projections on the musical cylinder. Other types of water organ were played out of sight and were used to simulate musical instruments apparently being played by statues in mythological scenes such as 'Orpheus playing the viol', 'The