Tube-casts are formed in most, if not all, conditions of kidney deterioration. To a limited extent also, they occur apart from other evidences of deterioration. This fact, bearing on the diagnosis of early renal disease, warrants a close study of their origin and significance.
The literature on the subject discloses many divergent views, of which even a partial review cannot be given. The objects here intended are to consider certain primary differences in casts and to account for their origin.
Tube-casts may originate from a number of the materials entering into the structure and composition of the kidney and blood, unchanged chemically and morphologically, or broken down and altered by processes of degeneration or by the action of the urinary secretion. It is evident therefore that uniformity of composition cannot be looked for. The protein units forming cellular matter are complex and subject to great variations, and so also are