Chapter XXV.

1. Those insects which are not carnivorous, but live upon the juices of living flesh, as lice, fleas, and bugs, produce nits from sexual intercourse; from these nits nothing else is formed. Of these insects the fleas originate in very small portions of corrupted matter, for they are always collected together where there is any dry dung. Bugs[180] proceed from the moisture which collects on the bodies of animals: lice from the flesh of other creatures; for before they appear, they exist in little pimples which do not contain matter: and if these are pricked, the lice[181] escape from them. Some persons have been afflicted with a disease arising from excessive moisture in the body, of which people have died, as they say that Alcmon the poet, and Pherecydes of Syria did.

2. And in some diseases lice are very common. There is a kind of lice, which they call wild, and are harder than the common sort, which are difficult to eradicate from the body. The heads of children are most subject to be infested with lice, and men the least so, for women are more liable to them than men. Those that have lice in the head are less subject to headache. Many other animals are infested with lice: for both birds have them, and those which are called phasiani, unless they dust themselves, are destroyed by them. And so are all those creatures which have feathers with a hollow stem, and those which have hair, except the ass, which has neither lice nor ticks. Oxen have both; sheep and goats have ticks, but no lice; hogs are infested with large, hard lice, and dogs with those which are called cynoraïstæ. All lice originate in the animals that are infested with them. All creatures that have lice, and wash themselves, are more liable to them when they change the water in which they bathe.

3. In the sea is a kind of lice[182] growing on fish; but these do not originate in the fish, but in the mud. Their appearance is that of wood-lice with many feet, except that they have a wide tail. There is one species of marine lice which occur everywhere, and especially infest the trigla. All these creatures are furnished with many legs, are exsanguineous, and insects. The œstrus[183] of the thynnus occurs near the fins: in shape it is like a scorpion, and as large as a spider. In the sea between Cyrene and Egypt, there is a fish called the phtheira, which accompanies the dolphin; it is the fattest of all fish, because it enjoys an abundance of the food which the dolphin hunts for.