The sense of craving, psychologically, is a demand for gratification; physiologically, a demand for material to correct some histological deficiency. It may be active and passive, normal and abnormal. It is associated with health, and may become a dominant feature in disease. By force of habit as relates to intoxicants, it is the principal factor of a disease. Great demands on the system will often arouse it to an extraordinary degree, in particular, in the puerperal state, and likewise among soldiers that have been for a long period in an active military campaign.

But there may be a therapeutic craving connected with disease that can only be cured by satisfying the demands of the craving.*

Where it is strongly manifested as in chlorosis, and in gestation, as is usually the case, although if of a morbid and ridiculous aspect in itself, it is well to give it attention, and determine what nature demands. What was the matter with the pregnant woman that craved a bite from her butcher's shoulder, a story once told in one of our medical lecture rooms? Should such a case actually occur, what would be the diagnosis? In all probability a deficiency of the phosphates in the woman's system. She selected the butcher intuitively through some association with the very material she needed. Why the craving was not meat itself, may have been owing to a hysterical fancy, or as but a partial part in the meat was required. Craving is never over-wise in asking what is really needed, except sometimes in diet, where all animal life through instinct are governed by the same laws.

Now and then we learn of a case where by gratifying the craving of a certain kind of a diet, a cure of the disease is made, which before resisted all medication. Dr. T. K. Griffith reported a case of this kind - an obstinate nurse's sore mouth which had resisted the usual local and constitutional treatment. At the time ripe tomatoes made their appearance she eagerly craved them as food, and she was allowed to eat them. An immediate improvement followed, the mouth healed, the appetite returned, and the patient gained strength and got well.

To show that we cannot always accept craving as a guide, in the treatment of diseases, I will cite a case. I once had in my military experience. An officer of high rank was under my treatment for dysentery, which finally terminated in convalescence. As his appetite returned, he strongly craved hard-boiled eggs. I positively forbade him to eat them; but nevertheless he ate them, and with a keen relish. But the eggs refused digestion, he was thrown at once into a relapse of the disease, closely associated with a collapse in which he died.