The staining kit: silver methenamine according to JONES (PAS-M) allows selective highlighting of specific cell structures and tissue components, especially in renal biopsies. This is achieved by combining silver methenamine and periodic acid-Schiff staining. The chemical composition includes silver methenamine borax, periodic acid, gold chloride, sodium thiosulfate, nuclear red, and semicarbazide solution. The special mixture of these chemicals enables highly sensitive staining that supports accurate diagnosis of kidney diseases such as glomerulonephritis. Basement membranes, mesangium and fibrils are effectively highlighted by silver methenamine staining, while periodic acid oxidizes sugar molecules to enhance silver binding. Gold chloride and sodium thiosulfate reduce excess silver and remove excess gold chloride, while nuclear red and semicarbazide help stain cell nuclei and stabilize staining.