The cavities in the upper part of the head of the sperm whale contain an oily liquid, which, after the death of the animal, concretes into a white, spongy mass, consisting of spermaceti mixed with oil. This mass is removed and allowed to separate by draining or pressure in the cold. Common whale oils and the oils from other cetaceous animals contain also small quantities of spermaceti, which on standing they slowly deposit,

Spermaceti is a concrete, fatty substance, a white, pearly, semi-transparent mass of neutral reaction and crystaline foliaceous texture, friable and somewhat unctuous to the touch, slightly inodorous and insipid ; it is insoluble in water, but soluble in the fixed oils ; its specific gravity is 0.945, or 18° Baume, and it melts at about 122° F. and congeals near 113° F. It is soluble in ether, chloroform, disulphide of carbon, and in boiling alcohol, from which latter, however, it separates in crystalline scales on standing. It is seldom found pure in commerce, but is adulterated with fixed oils. Cetinelaic acid is the main constituent of spermaceti, and is different from oleic acid. Spermaceti also contains small quantities of stearic acid, myristic and lauro-stearic acids. Pure spermaceti does not produce fatty spots on paper. When old it becomes darker colored and rancid. Different from stearin, spermaceti is not affected by boiling in diluted solution of carbonate of soda.

Sperm Oil - Is the limpid liquid separated from the spermaceti, the spongy mass in the head of the dead sperm whale. It is a pale, yellowish-colored liquid, with a smell of fishy nature, and will, when exposed to the cold, deposit but little solid matter. It is not liable to become rancid, has no corrosive action on metal, and no tendency to dry and become gummy. It retains its viscosity under influence of heat better than any other oil. Sperm oil is a compound of fatty acids with alcohol radicals, the acids belonging to the oleic acid series. Sulphuric acid gives rise to an increase of heat of some 120° F., and produces a yellowish-brown mass, which distinguishes sperm oil from other fish oils. It differs from other fish oils also by its chemical constitution and its low specific gravity, 0.884 at 60° F., 28° to 29° by Baume. It is the lightest of all natural oils.

Seal Oil - Is obtained from the blubber of the hooded seal, the barbed seal and the harp seal of the polar regions. The oil is extracted from the blubber the same as from that of the whale, and its properties are similar to the whale oil. Its color varies from a light straw to a brown. It is a strongly odorous oil, of a specific gravity of 0.924 to 0.929, 21° Baume.