1. Sheep and goats live upon grass. Sheep pasture for a long while in one place without leaving it, but goats change their places very soon, and only crop the top of the grass. The sheep fatten rapidly with drinking, and for this reason during summer they give them salt, a medimnus to each hundred sheep; for in this manner the flock becomes more healthy and fat, and frequently they collect and bring them together for this purpose, that they may mix a great deal of salt with their food; for when thirsty they drink the more. And in the autumn they feed them with gourds which they have sprinkled with salt, for this makes them give more milk. When driven about in the heat of the day they drink more towards evening. If fed with salt after parturition, the udder becomes larger. 2. Sheep fatten on green shoots, vetches, and all kinds of grass, and they fatten more rapidly when their food is salted. They fatten more rapidly if previously starved for three days. During autumn northern water is better for sheep than southern, and pastures towards the west are good for them. Long journeys and weariness make them lean. Shepherds distinguish the strong sheep during winter by the frost adhering to their wool, which is not the case with those that are sick; for those that are not strong move about in their weakness and shake it off. 3. The flesh of all quadrupeds which feed in marshy grounds is inferior to that of those which live on high ground. Sheep with wide tails endure the winter better than those with long tails, and short woolled-sheep better than long-woolled, and those with curly wool are more affected by the cold. Sheep are more healthy than goats, though goats are the stronger. The fleece and the wool of sheep which have been devoured by wolves, and garments made of such wool are more subject to vermin than others. CHAPTER XIII. 1. Those insects which have teeth are omnivorous, but those which have a tongue only live upon fluids, which they collect from all sources with this organ. Some of these are omnivorous, for they feed upon all kinds of fluids, as the fly. Others only suck blood, as the myops and œstrus. Others, again, live upon the juices of plants and fruit. The bee is the only insect that never touches anything putrid. It uses no food that has not a sweet taste. They also take very sweet water, wherever they fall upon any that is pure. The different kinds of animals then use these kinds of food. CHAPTER XIV.