Section 103. (6) _The Illusions of the Olfactory Sense_.
Olfactory illusions are very rare in healthy people and are hence of small importance. They are frequent among the mentally diseased, are connected in most cases with sexual conditions and then are so vivid that the judge can hardly doubt the need of calling in the physician. Certain poisons tend to debauch the olfactory sense. Strychnine, e. g., tends to make it finer, morphine duller. People with weak lungs try, in most cases, to set their difficulty of breathing outside themselves and believe that they are inhaling poisoned air, coal-gas, etc. If one considers in this connection the suspiciousness which many people suffering from lung trouble often exhibit, we may explain many groundless accusations of attempted murder by stifling with poisonous or unbreathable gas. If this typical illusion is unknown to the judge he may find no reason for calling in the physician and then--injustice.
The largest number of olfactory illusions are due to imagination. Carpenter's frequently cited case of the officials who smelled a corpse while a coffin was being dug up, until finally the coffin was found to be empty, has many fellows. I once was making an examination of a case of arson, and on approaching the village noted a characteristic odor which is spread by burned animals or men. When we learned: that the consumed farm lay still an hour's ride from the village, the odor immediately disappeared. Again, on returning home, I thought I heard the voice of a visitor and immediately smelled her characteristic perfume, but she had not been there that day.
Such illusions are to be explained by the fact that many odors are in the air, that they are not very powerfully differentiated and
may hence be turned by means of the imagination into that one which is likely to be most obvious.
The stories told of hyper-sensitives who think they are able to smell the pole of a magnet or the chemicals melted into a glass, belong to this class. That they do so in good faith may be assumed, but to smell through melted glass is impossible. Hence it must be believed that such people have really smelled something somewhere and have given this odor this or that particular location. Something like this occurs when an odor, otherwise found pleasant, suddenly becomes disgusting and unbearable when its source is unknown. However gladly a man may eat sardines in oil he is likely to turn aside when his eyes are closed and an open can of sardines is held under his nose. Many delicate forms of cheese emit disgusting odors so long as it is not known that cheese is the source. The odor that issues from the hands after crabs have been eaten is unbearable; if, however, one bears in mind that the odor is the odor of crabs, it becomes not at all so unpleasant.
Association has much influence. For a long time I disliked to go to a market where flowers, bouquets, wreaths, etc., were kept because I smelled dead human bodies. Finally, I discovered that the odor was due to the fact that I knew most of these flowers to be such as are laid on coffins--are smelled during interment. Again, many people find perfumes good or bad as they like or dislike the person who makes use of them, and the judgment concerning the pleasantness or unpleasantness of an odor is mainly dependent upon the pleasantness or unpleasantness of associative memories. When my son, who is naturally a vegetarian and who could never be moved to eat meat, became a doctor, I thought that he could never be brought to endure the odor of the dissecting room. It did not disturb him in the least, however, and he explained it by saying: ``I do not eat what smells like that, and I can not conceive how you can eat anything from the butcher shops where the odor is exactly like that of the dissecting room.'' What odor is called good or bad, ecstatic or disgusting, is purely a subjective matter and never to be the basis of a universal judgment. Statements by witnesses concerning perceptions of odor are valueless unless otherwise confirmed.
Section 104. (b) Hallucinations and Illusions.
The limits between illusions of sense and hallucinations and illusions proper can in no sense be definitely determined inasmuch
as any phenomena of the one may be applied to the other, and vice versa. Most safely it may be held that the cause of illusions of sense lies in the nature of sense-organs, while the hallucinations and illusions are due to the activity of the brain. The latter are much more likely to fall within the scope of the physician than sense- illusions, but at the same time many of them have to be determined upon by the lawyer, inasmuch as they really occur to normal people or to such whose disease is just beginning so that the physician can not yet reach it. Nevertheless, whenever the lawyer finds himself face to face with a supposed illusion or hallucination he must absolutely call in the physician. For, as rarely as an ordinary illusion of sense is explicable by the rules of logic or psychology, or even by means of other knowledge or experience at the command of any educated man, so, frequently, do processes occur in cases of hallucination and illusion which require, at the very least, the physiological knowledge of the physician. Our activity must hence be limited to the perception of the presence of hallucination or illusion; the rest is matter for the psychiatrist. Small as our concern is, it is important and difficult, for on the one hand we must not appeal to the physician about every stupid fancy or every lie a prisoner utters, and on the other hand we assume a heavy responsibility if we interpret a real hallucination or illusion as a true and real observation. To acquire knowledge of the nature of these things, therefore, can not be rigorously enough recommended.