本方法涉及纸张中动物胶的定性和定量测定，其数量用于高级纸张的上浆（1）。它适用于用甲醛、明矾或氨基甲醛树脂硬化的胶水，以及照相纸。该方法也可用于测定明胶（一种更精细的动物蛋白质）。该方法基于埃利希试剂（对二甲基氨基苯甲醛）与羟脯氨酸（胶原蛋白衍生的氨基酸之一）的显色反应。它专门用于胶水和明胶； 其他含氮物质不会产生干扰。给出了两种基本相同的定性方法:一种是至少有100 mm2纸张可用的宏观方法，另一种是只能使用10 mm2纸张的微观方法。定量程序的范围见3.1。

This method deals with the qualitative and quantitative determination of animal glue in paper in quantities that are used for sizing high grade papers (1). It is applicable to glue hardened with formaldehyde, alum, or amino-formaldehyde resins, and to photographic papers. This method can also be used in the determination of gelatin (a more highly refined form of animal protein).The method is based on the color reaction of Ehrlich's reagent (p-dimethyl aminobenzaldehyde) with hydroxyproline, one of the amino acids derived from collagen. It is specific for glue and gelatin; other nitrogenous materials do not interfere.Two qualitative procedures are given, which are essentially the same: a macromethod where at least 100 mm2 of paper is available and a micromethod where only 10 mm2 can be used.The scope of the quantitative procedure is given in 3.1.