Previously, we(1) reported about the chemical and physical properties of oils contained in various parts of a sperm whale body, and found noticeable differences among these oils. This time, we studied on the quantitative composition of fatty acids of sperm whale head. cavity oil. The results obtained are shown in Table 1 to Table 8. The following facts were noticeable. The amounts of saturated and unsaturated acids were nearly equal. Very large quantity of lower fatty acids (less than C14) was present.