In referring to such cases Cannon has concluded: “All these observations clearly demonstrate that the normal flow of the first digestive fluids, the saliva and the gastric juice, is favored by the pleasurable feelings which accompany the taste and smell of food during mastication, or which are roused in anticipation of eating when choice morsels are seen or smelled. These facts are of fundamental importance in the serving of food, especially when, through illness, the appetite is fickle. The degree of daintiness with which nourishment is served, the little attentions to æsthetic details—the arrangement of the dishes, the small portions of food, the flower beside the plate—all may help to render food pleasing to the eye and savory to the nostrils, and may be the deciding factors in determining whether the restoration of strength is to begin or not.” _The Function of Taste in the Organic Economy_ The preliminary nature of these anticipatory secretions of the digestive juices is by no means an adequate measure of their ultimate importance. Studies of the mechanism of digestion show that each stage, as it occurs, either directly or indirectly, through its product, affords the appropriate stimulus which evokes the following stage. Thus, continued flow of gastric juice is provided for by the action of the preliminary flow or its products on the walls of the stomach; and other juices, such as the bile and the pancreatic, are in turn released by the action of this continued flow. The pleasurable sensations of taste are thus the initial stimulus to the whole series of digestive processes. Even in the absence of hunger these sensations seem potent to initiate the digestive mechanism. Among the most interesting of recent physiological studies are those showing the very great sensitivity of the important organic mechanisms, especially those of secretion, to such experiences as shock, worry, fear, anger, grief, excitement, and pain. All these factors tend to retard the activity of the digestive system, while they may also be seen to reënforce the activity of other mechanisms. As opposed to the effect of these factors, pleasurable experiences connected with food serve not only to guide the organism in its choice, but play an important part in its effective appropriation and assimilation, through their action in setting the digestive mechanisms in action, and in guaranteeing the continuation of this action after the completion of the act of eating.