56 Asinus in Tegulis.
We can, therefore, see plenty of reasons why Trimalchio's donkey on the tiles should be res horribilis. He might be some sort of evil spirit ; his mere presence there might be a very bad omen ; he might be a new and particularly unde- sirable form of ghost. A less easy question to answer is why the harmless necessary roof should have so bad a reputation. I have no very convincing reply, but am inclined to think that a dozen fears of things real and unreal may have contributed, fairly early in the history of house-building man. The uncanny effect of firelight on the rude thatching and the smoke-wreaths ; the strange scratchings and patterings of small nocturnal animals running over the top of the hut ; nightmares in which the roof seemed to fall and crush the sleeper ; real injuries from the fall of a heavy bough on the flimsy structure, or the intrusion of some more than commonly enterprising beast of prey ; bats, moths, and small birds fluttering about inside ; all these and many other factors may well have united to make up the sum of these curious beliefs.
H. J. Rose.
University College, Aberystwyth.
