The lyophilic colloids differ in their protective power. The protective power is measured in terms of gold number. It may be noted that smaller the value of the gold number, greater will be the protecting power of protective colloids. Therefore, the reciprocal of gold number is a measure of the protective power of the colloid, gold number of gelatin, haemoglobin and sodium acetate are $5 \times 10^{-3}, 5 \times 10^{-2}$ and $7 \times 10^{-1}$, respectively, hence, the protective actions will be in the order : Haemoglobin $>$ gelatin $>$ sodium acetate