The problem we have to deal with is a startling one, as thus put before us by Mr. Wentz. Are these beings of the spirit world real beings, having a veritable existence of their own, in a world of their own, or are they only the creation of the imagination of his informants, and the tradition of bygone centuries? The newspaper, the 'National' School, and the _Zeitgeist_ have answered to their own entire satisfaction that these things are imagination pure and simple. Yet this off-hand condemnation does not always carry with it a perfect conviction. We do not doubt the existence of tree-martins or kingfishers, although nine hundred and ninety-nine people out of every thousand pass their entire lives without being vouchsafed a glimpse of them in their live state; and may it not be the same with the creatures of the spirit world, may not they also exist, though to only one in a thousand it be vouchsafed to behold them? The spirit creatures cannot be stuffed and put into museums, like rare animals and birds, whose existence we might doubt of if we had not seen them there; yet they may exist just as such animals and birds do, though we cannot see them. I, at least, have often been tempted to think so. But the following considerations, partly drawn from comparative folk-lore, have made me hesitate about definitely accepting any theory. In the first place, then, viewing the Irish spirit-world as a whole, we find that it contains, even on Mr. Wentz's showing, quite a number of different orders of beings, of varying shapes, appearances, size, and functions. Are we to believe that all those beings equally exist, and, on the principle that there can be no smoke without a fire, are we to hold that there would be no popular conception of the banshee, the leprechaun, or the _Maighdean-mhara_ (sea-maiden, mermaid), and consequently no tales told about them, if such beings did not exist, and from time to time allow themselves to be seen like the wood-martin and the kingfisher? This question is, moreover, further complicated by the belief in the appearance of things that are or appear to be inanimate objects, not living beings, such as the deaf coach or the phantom ship in full sail, the appearance of which Mr. Yeats has immortalized in one of his earliest and finest poems.