Taste, as we usually understand it, really involves, as is well known, an element of smell, and taste dreams of this kind seem to occur from time to time under the influence of any slight disturbance of the mucous membrane of the mouth or slight indigestion. It is possible that the latter element was present in the following dream: I imagined that, following the example of a friend, I gave some cigarettes to a tramp we had casually met, and that, in return, we felt compelled to drink some raw gin he carried. I did so with some misgiving as to the possible results of drinking from a tramp's flask, but although in real life I had not tasted gin for many years, the hot burning taste of the spirit was very distinct. On awakening, my lips seemed hot and dry, and it was doubtless this labial sensation which led dream consciousness to seek a plausible explanation in cigarettes and spirits. Although the spirit seemed to have the specific flavour of gin, it is always difficult, if not impossible, in dream sensations, to distinguish between what one feels and what one merely concludes that one feels. In such a case, that is to say, it remains doubtful whether the labial sensation evokes the specific hallucination of gin, or whether it merely suggests to sleeping consciousness that the gin has been tasted, much as it is possible to suggest to the hypnotised person that the substance he is tasting is a quite different substance, that salt is sugar, or that water is wine. As with dreams of smell, it is not always possible to detect any external stimulation as the cause for a taste or pseudo-taste dream.[66] This may be illustrated by a dream which belongs strictly to the tactile class; I dreamed that I called upon a medical acquaintance whose assistant I found in a dark surgery. I absently took up a broken medicine bottle and put it to my mouth, when my friend came in. I spoke to him on some medical topic, but he entered his carriage, and was driven off before he had time to answer me. I then found that my mouth was full of fragments of broken colourless glass, which I carefully removed. This dream was constructed, in the manner which has been often illustrated in the previous pages, of small separate incidents which had occurred during the immediately preceding days. One of the incidents was the fact that I had myself smashed a little coloured (not colourless) glass and carefully picked up the fragments. But the vividest part of the dream was the sensation of broken glass in the mouth, and on awaking no sensation could be detected in the mouth. So that though the most plausible explanation of such a dream would be the theory that the recent experience with broken glass had suggested to sleeping consciousness the explanation of an unpleasant sensation actually experienced in the mouth, there was nothing whatever to support that theory.