But this is not the only erroneous physiological doctrine which emanates from the supporters of Dr. Dewey, for they boldly assert that normal hunger is never manifested in the stomach, but, like thirst, always in the glands of the throat and mouth. To account for the all-gone sensation in the pit of the stomach, which is usually associated with the desire for food, they declare that this is not normal hunger, which indeed has never been experienced from the days of infancy. The sensation usually felt is the abnormal craving of a morbid diseased appetite and the indication of a congested stomach. When, therefore, our stomach objects that it has not been supplied with its normal requirements in the way of breakfast, that is accounted for by suggestion and the sudden withdrawal of the stimulation produced by food. On the other hand, the headache which is the usual penalty of omitting our breakfast is due to the lack of withdrawal of its excess of blood for the purpose of digesting the ingested food, all unconscious of the fact that if this were the explanation the headache should have existed prior to the administration of food and be relieved by partaking of it.

Dr. Haig's explanation of this headache is equally interesting. He believes that the greater quantity of uric acid is excreted between 4 a.m. and breakfast-time, and that but for the intervention of this meal, usually containing large quantities of purins or xanthins, the excretions would continue. Should this meal be omitted, however, by those who are in the habit of consuming tea, coffee, and animal food, then a uricacidaemia is set up with all its ill-effects, of which headache is perhaps the most severe. Whatever truth there may be in this explanation, it is natural and consistent with his theoretical views on diet; but presumably Dewey's disciples would argue that whether a person were living on a purin-free diet or not, the supervention of a headache would be likely to follow the omission of breakfast. Haig, on the other hand, teaches that headaches would not be likely to arise even on desisting from this meal, so that the theoretical explanation advanced by Dewey cannot be correct.

From the facts which we have adduced it is quite evident that the penalty for the omission of breakfast is not always the supervention of a headache, and when this does arise it is in most cases the manifestation of a "craving" for tea, coffee, or other toxic alkaloid. Every stimulation leaves behind it a residual impression. Continual repetition of the stimulation intensifies the impression, and tends to create a desire which can only be satisfied by an increase of the stimulus. The headache of tea-drinkers may be a congestion of the vessels of the cerebral cortex, which is only relieved by a repetition of the dose, or it may be some alteration of the neurones, necessitating readjustment. The subject is one still requiring much elucidation and is closely bound up with the physical explanation of habit. Pavlov asserts that "every food determines a certain amount of digestive work, and when a certain given dietary is long continued, definite and fixed types of gland activity are set up, which can be altered but slowly and with difficulty. In consequence, digestive disturbances are often instituted if a change be suddenly made from one dietetic regime to another," and this may very well depend on the secretion of gastric juice at the accustomed time. This is unquestionably the cause of the nausea and faintness often experienced, especially by women, when no food is supplied at the customary period, whilst in others, especially in men with a tendency to hyperchlorhydria, actual pain may arise.