Smell and taste, by the way, are usually regarded not only as allied senses, but also as if they were akin in their nature and function. Allied they are, undoubtedly, seeing that both subserve the function of food-perception. But the resemblance ends there. For, of the two, smell is at once the more delicate and the more extensive in capacity, and, as they differ widely in their anatomical structure, there can be no doubt but that in physiological action also they are dissimilar. The taste-bulbs are capable of appreciating four sensations only, and these quite simple, while the capacity of the olfactory organ, as we shall see more fully later on, is practically unlimited. All the subtlety of “taste,” all that we call “flavour,” is an olfactory sensation. Thus, people devoid of the sense of smell cannot discern the finer savours. They would be unable to distinguish, say, a vanilla from a strawberry ice. All they could tell would be that both were cold and sweet. The popular phrase which refers the appreciation of the finer shades of taste to the “palate” we may therefore look upon as an attempt to express the feeling that delicate flavours are sensed somewhere higher up than in the mouth. So that a “man of taste” is really a man of smell, and all the literary eloquence in praise of wine and dainty food, to say nothing of the more prosy cookery books, is, in reality, a general hymn of adulation offered unwittingly to the nose! Compared with sight and hearing, however, smell in man is only one of the minor senses. But, as if to make up for a position so inferior, it is remarkable as being the most subtle of all our senses, possibly, as some hold, because of the ancestral appeal to our (more or less repressed) animal nature. So subtle is it, indeed, that I am persuaded its stimuli may not, on occasion, emerge into consciousness at all. They remain below the threshold. So that, although subjected to their influence, we may remain ignorant of the cause of that influence. For smell often operates powerfully, not only in surreptitiously enriching and invigorating the mental impression of an event, but also in directing at times the flow of ideas into some particular channel independent of the will. The influence of the perfume of a woman’s hair in unexpectedly arousing a feeling of intimacy will appeal to the male reader as a good example of this upsurging interference with the placid flow of normal ideation. Perhaps, also, this is the explanation of a strange and rather unpleasant ghost-story I once heard. I dare not vouch for the truth of it, but as it bears upon the subject we are considering, I give it here, not without misgiving, for what it is worth. For the sake of verisimilitude I shall relate it pretty much in the narrator’s own words: