There are other helps to digestion, and the chief of these is exact mastication, which greatly forwards the work of the stomach: this is highly recommended by physicians; but slighted by others very foolishly, and greatly to their own prejudice. It both increases the secretion of the saliva, which is the best menstruum of the aliments, and, whilst it divides the latter into minute particles, it increases their superficies, whence they are more easily penetrated by the gastric juices; consequently there is a quicker digestion, a more compleat solution, no spontaneous corruption, no irritating of the stomach. Therefore let not the learned despise mastication, or rather not forget it, whilst at their meals they are, by a pernicious habit, intent upon other things: whether they read or meditate, the stomach suffers, because the nerves languish when the mind thinks attentively, and experience proves to the very eyes themselves, that digestion is badly performed when the nerves languish; for upon binding the nerves of the stomach, the illustrious HALLER, who made so many extraordinary discoveries, often saw the aliments totally corrupted, instead of being digested. Digestion is performed slowly in men of learning, therefore fresh aliments should seldom be given them; because the state of the stomach is very different when it is half full of undigested aliments, from what it is when entirely void of aliments, and overflowed with the gastric fluids, ready for the use of concoction. Therefore to make three meals a day, one somewhat considerable, the other two rather slight, will be sufficient for men of learning. The following order with regard to eating, or rather living, pleases me highly, and is recommended by the experience of numbers: Upon rising in the morning a studious person should drink a glass of pure water; in about an hour after he should breakfast; six hours after he should dine, having first past one hour in walking; after dinner he should allow himself an hour or two of leisure, because to sit down to study immediately after eating is highly pernicious: his supper should be light; for this, there are reasons of the greatest weight, because, as I observed before, sleep occasions a dangerous plethora in the head; therefore the fullness of the vessels should not be increased before sleep by too large a meal[45]: add to this, that the functions of the nerves are suspended during the time of sleep, and they cannot perform digestion; at last a soft and refreshing slumber is produced by the absence of all irritation: but if the stomach is overloaded with aliments, the sleep is interrupted, as the nerves are continually affected by the irritation of digestion. Hence a plentiful supper causes a heaviness in the head, sleep is disturbed, digestion interrupted, the strength impaired, and the health entirely destroyed. But a Platonic supper is praised, because it is not only agreeable at the time, but the day following.