 The spermaceti organ is like a large barrel of spermaceti . Its surrounding wall , known as the case , is extremely tough and fibrous . The case can hold within it up to 1 @,@ 900 litres of spermaceti . It is proportionately larger in males . This oil is a mixture of triglycerides and wax esters . The proportion of wax esters in the spermaceti organ increases with the age of the whale : 38 – 51 % in calves , 58 – 87 % in adult females , and 71 – 94 % in adult males . The spermaceti at the core of the organ has a higher wax content than the outer areas . The speed of sound in spermaceti is 2 @,@ 684 m / s ( at 40 kHz , 36 ° C ) , making it nearly twice as fast as in the oil in a dolphin 's melon . 
