Human duodenal epithelium. Peroxisomes are stained with DAB at pH 10.5 by their catalase activity and postosmicated. 0.5 µm plastic section were visualized using electron microscopy at low magnification. Image shows thin worm like peroxisomes. Three large dark round structures are lysosomes. Brush border microvilli are well seen. More details in Roels et al: http://gut.bmj.com/content/32/8/858.long