I must here repeat Briquet’s remark on this point: “However strange these appetites may appear, their origin can frequently be discovered. Thus a young woman, who would greedily devour the embers of her foot-warmer, told me that she had, from the beginning, been fond of the crust of bread; from this she came to like the crust of toasted bread, then charred bread, and so gradually acquired the taste for small pieces of charcoal. I am inclined to think that, were we to inquire into the origin of many of these strange tastes, we should find it as simple as the above.” Pierre Janet (_État mental des hystériques_, ii. p. 71) transcribes this passage, and adds, “I have often followed this advice and been in a position to appreciate its value.” This psychological inquiry is very ingenious, but only removes the difficulty a stage further back. It shows us through what series of associations the final result is attained; but association alone is not sufficient to arrive at this result, still less to render it permanent. It is only the external mechanism which explains, at the utmost, why the deviation should have taken this particular direction. Many persons are fond of crust, even of burnt crust, who will never come to have the slightest appetite for charcoal. Many have eaten charcoal out of curiosity, or by accident, but without acquiring a taste for it. It is some deeper and more powerful cause than association which lies at the root of these feelings and renders them active. There are many instances of hypochondriacs searching for and devouring with enjoyment worms, toads, spiders, caterpillars, etc.; and the beginning of insanity is often marked by an eccentric and disordered dietary. Again, at a still lower stage, we have coprophagy and scatophagy (the swallowing of excrements, urine, the contents of spittoons, etc.), which are rarely, if ever, found in any but idiots and those suffering from dementia, _i.e._, in beings whose simplest instincts have been abolished or perverted. The voracity of certain idiots has been attributed to paralysis of the gastric branch of the vagus nerve.[130] ----- Footnote 130: For details, see Campbell “On the Appetite in Insanity,” in the _Journal of Mental Science_, July 1886, pp. 193 _et seq._, and Belmondo, “Pervertimenti dell’istinto di nutrizione,” in Tamburini’s _Rivista_, 1888, pp. 1 _et seq._, where is cited the case of an insane patient in whose stomach were found 1841 objects, such as nails, bits of lead, and the like, weighing in all eleven (English) pounds, ten ounces. ----- The same would apply to the sense of smell, so intimately associated with that of taste that it has justly been called “tasting at a distance.” (We must not, moreover, forget its close connection with the sex-instinct.) Certain persons, who cannot endure the most delicate aromas, enjoy the odour of valerian, of asafœtida, and of still more repulsive substances.