Morphometric analysis of glomeruli allows to estimate renal maturity or find out an accidental retardation of growth. A simpler estimation of the number of yalers formed by immature glomeruli is less time-consuming. Final diagnosis of pathologist should include this estimation. An intense growth of glomeruli does not start before glomerular lobulation concurring with an increase of capillary lumina in a glomerular square unit. So lobulation expresses generally the maturity of glomeruli.