Chapter XIII.

1. Adeps and fat differ from each other, for fat is always brittle, and coagulates upon cooling, but adeps is liquid, and does not coagulate; and broths made from animals with adeps do not thicken, as from the horse and hog, but that made from animals with fat thickens, as from the sheep and goat. These substances also differ in situation, for the adeps is between the skin and the flesh; but the fat only exists upon the extremity of the flesh. In adipose animals the omentum is adipose, in fat animals it is fatty: for the animals with cutting teeth in both jaws are adipose, those that have not cutting teeth in both jaws are fat.

2. Of the viscera in some animals the liver is full of adeps, as in the cartilaginous fishes, for oil is procured from these during the process of decomposition, the cartilaginous fish are particularly free from adeps on their flesh, but the adeps is separated on the stomach. The fat also of fishes is adipose, and does not coagulate; and some animals are furnished with adeps on the flesh, and others apart from the flesh; and those creatures in which the adeps is not separated from the flesh have less of this substance on the stomach and omentum, as the eel: for these creatures have little fat on the omentum. In most animals the adeps collects principally upon the abdomen, especially in those which take little exercise.

3. The brain of adipose animals is unctuous, as in swine; that of fatty animals is dry. Of all the viscera the kidneys are surrounded by the greatest quantity of adeps in all animals; that on the right side is always the least adipose; and let there be ever so much adeps, there is always a space left between the kidneys. They are also the most fatty of the viscera, and especially in sheep, for this animal sometimes dies from the entire concealment of its kidneys in fat. This excessive fat around the kidneys arises from good pasture, as in the Leontine territory of Sicily; wherefore also in the evening they drive away the sheep which have been feeding during the day, in order that they may take less food.

4. The fat around the pupil of the eye is common to all animals; for all have fat in this part, that possess it, and are not hard-eyed. Fat animals, both male and female, are more inclined to be barren, and all old animals become fat more readily than young ones, especially when they increase in depth, having obtained their proper width and length.