However, the larger fragments of algae and other food particles seen in
concrement vacuoles in fiber cells (Grell and Benwitz, 1971; Wenderoth, 1986) must have been transferred there from other cells with direct access to the surface of the animal.
The process of stone formation changes, to a greater or lesser extent, the composition of the urine, i.e., the concentration(s) of lithogenic substance(s) before and after a growing
concrement is passed must be different (Fig.
Further, in 20-40% of cases if not to carry out preventive maintenance, the crystalluria comes to the end with
concrement formation (Baumann et al., 2003).