The reports of Kimmelstiel and Wilson 1 and Murakami,2 in 1936, established the identity of special glomerular lesions in association with diabetes mellitus. Since then considerable interest has centered about the location, composition, and pathogenesis of glomerular changes in diabetes. In this communication we wish to record the results of the application of a series of histochemical procedures to the kidneys from six diabetic subjects. Sections from these kidneys, prepared by the usual techniques, demonstrated the glomerular lesions of diabetes as described in the literature.*The findings presented herein serve to add emphasis to the presence of a multiplicity of ingredients within certain of the diabetic glomerular lesions. The observations reflect on the general problem of vascular hyalin by distinguishing further between "cellular hyaline lesions" and "acellular hyaline lesions" within the glomeruli. Also, additional support for the smooth-muscle origin of certain forms of vascular hyalin is presented.Review of Literature Different points of view have evolved since the discussions of 1936.\s=d\ In order to attempt to establish the relationship of the present findings to various avail¬ able descriptions and interpretations, a general review of the literature appears appropriate at this time. Composition and Location of Glomerular Lesions of DiabetesKimmelstiel and Wilson (1936) desig¬ nated the spherical hyaline lesions which they observed in the kidneys from eight diabetics as "intercapillary glomerulosclerosis" because they interpreted the source of the lesion as sclerosis and hyalinization of the "intercapillary connective tissue" of the glomerulus. Allen3 (1941) demonstrated the presence of an endothelial-lined lumen within the lesion by means of serial sections and interpreted the evolution of the nodule as due to a progressive thickening of the capillary wall. Allen3 also reemphasized certain features of the lesion and added to an understanding of its make-up. These as¬ pects may be summarized as follows: (1) The lesions are cellular, but the cellularity varies, consisting mainly of two or three concentric layers of flattened cells at the periphery and an occasional nucleus within the core. (2) A concentric fibrillar structure can be demonstrated by silver stains. (3) The nodular lesion is essen¬ tially collagenous but during its development it may contain ingredients possessing staining properties of noncollagenous type. (4) The nodule resists tryptic digestion in contradistinction to

No abstract