Amyloid is a substance that has the same composition of the basic qualities even in the different patterns of amyloidosis. Electron microscopic investigations have revealed that all forms of amyloidosis do not only exhibit homogeneous basic qualities but also common principle of accumulation. This may be commented as follows: Fibrils of amyloid are always found in close connection with basement membranes or basement membrane-like substances respectively produced by cells with the property of contracting (myocytic or "myopotent' cells). Collagen fibres of different types do not display a regular relation to the substance of amyloid. The origin and development of the various forms of amyloidosis depends on the three following factors: 1. On the extent of the production of amyloidogenic proteins which may belong to different types of proteins according to the basic disease; 2. On the way of protein silting (hematogenic silting-generalized amyloidosis; local enrichment--local amyloidosis); 3. On the site of predilection of all deposits of amyloid in the areas of basement membranes or basement membrane-like substances resp. produced by cells with the properties of contracting. A new classification should be made on the basis of these principles.