Fish meal is characterized for animal-feeding purposes by a proximate analysis for protein, oil, moisture, and ash. In shellfish meals, this analysis gives erroneously high results if no correction is made for the apparent protein contributed by chitin, an N-acetylated glucosamine polysaccharide. This shortcoming has been recognized by South African workers (Black and Schwartz 1950), who have devised a method for the estimation of chitin and chitin nitrogen.