The only drawback is that fat makes the food "rich" and difficult of digestion—unless the cook is an artist.
This is why so many persons exclude it from their dietary, at the cost of energy in men and the beauty of health in women.
It is here that salad comes to the rescue. The vinegar in it, if genuine, excites by its fragrance and acidity the digestive glands not only in the mouth and the stomach, but in the pancreas, which acts on all the constituents of food, particularly the fats.
The pancreas is a gland near the stomach; it secretes the juice known as pancreatic and pours it into the duodenum, or small intestine, which—some ten or fifteen feet in length, is folded about it. To prevent intestinal indigestion there must be an abundant flow of pancreatic juice, and this flow is stimulated by the vinegar in the salad we eat and other acids in our food.
On this point the greatest living authority on the subject, Professor Pawlow, makes the following extremely important remarks:
... an acid reaction is not only necessary for an efficient action of the peptic ferment, but is at the same time the strongest excitant of the pancreatic gland. It is even conceivable that the whole digestion may depend upon the stimulating properties of acids, since the pancreatic juice exerts a ferment action upon all the constituents of the food. In this way acids may either assist digestion in the stomach where too little gastric juice is present, or bring about vicarious digestion by the pancreas where it is wholly absent. It is easy, therefore, to understand why the Russian peasant enjoys his kwas with bread. The enormous quantity of starch which he consumes, either as bread or porridge, demands a greater activity upon the part of the pancreatic gland, and this is directly brought about by the acid. Further, in certain affections of the stomach, associated with loss of appetite, we make use of acids, both from instinct as well as medical direction, the explanation being that they excite an increased activity of the pancreatic gland, and thus supplement the weak action of the stomach. It appears to me that a knowledge of the special relations of acids to the pancreas ought to be very useful in medicine, since it brings the gland—a digestive organ at once so powerful and so difficult of access—under the control of the physician.
It is obvious from these disclosures that if every American family followed the French custom of eating a sour salad at least once a day there would be very much less intestinal indigestion, which is even more distressing than indigestion in the stomach.
It is further obvious that Fletcherizing, or "mouth work," alone does not avert indigestion, for saliva has no effect on fats. The pancreas takes care of these, particularly if aided by acid ingredients in our food.
Probably no detail of the French menu is therefore so important to us as the daily sour salad.