( Originally Published 1934 )
In healthy or normal people the best check we have of the correctness and purity of the food eaten is the presence or absence of dreams upon retiring. In well people, with absolutely pure and proper food, there will be no dreams. Any food that causes much dreaming is unfit to be eaten. The amount and intensity of the dreams aroused by food is directly in proportion to the unfitness (badness) or poor quality of the food. This rule applies only to the healthy or normal individual.
The state of health of the individual modifies this rule. A sick person will dream more and be disturbed much more easily by the same food which does not disturb or arouse dreams in a well person. Ill people will be disturbed by dreams aroused by foods which are quite harmless and of good quality. People suffering with a cold will dream following the eating of food which would not have given rise to dreaming if the cold was not present. Bad food will cause dreaming in ill people directly in proportion to the degree of badness of the food and the severity of the illness.
The following is a general rule from which there are extremely few exceptions. The truly healthy person does not have disturbing dreams, providing no bad food has been eaten. Such an individual can scarcely remember the dreams he has had during his last sleep. The dreams of the night before are not remembered. Generally speaking, only disturbing dreams are remembered. In the case of well people, we may take it for granted that some bad food has been eaten if dreams are remembered. A person with even so much as a mild cold is not really healthy for the time being.
How simple the explanation of dreaming is once it is traced to the offending food. Occasionally apparently harmless foods will arouse quite a disturbing dream in even well or fairly well people. The explanation is again definite. The food eaten was at fault; it was not as harmless as it appeared to be. For instance, if it was grapefruit, it might have been unripe, which is often the case where fruits are out of season.
Frequently, due to the many different and compounded foods we eat, it is just as difficult to determine the exact food which caused the disturbed dreams as it is to find the proverbial needle in the hay stack, but persistency wins.
It is questionable whether sicknesses or illnesses even if accompanied by fever will give rise to as much disturbance of the sleep and induce disturbing dreams to the degree as readily as bad food. Illnesses which are close to the brain, such as marked nasal sinus disease, are probably the chief exceptions to this rule; foods or poisons which act principally by injuring the brain are also in this last class.
As a rule, sick people who are receiving the antisepticizing treatments should sleep well, undisturbed by unpleasant dreams, again providing that they have not eaten bad or disagreeable food.