When we eat meat, this is passed down without change into the stomach, where its presence produces the flow of gastric juice, one ingredient of which is hydrochloric acid, and again it is not hard to see where it is wrong practice to combine starchy or sweet foods with this class, for it compels the presence of hydrochloric acid in the stomach as the first requisite for its conversion to lower forms, of course arresting the digestion of all carbon foods, which require alkalin conditions throughout.

With the hydrochloric acid is also produced pepsin and minor ferments, and the digestion of the protein is on.

First this concentrated form of protein must be acted on by the acid to soften its capsule, so that the pepsin can get to work to convert it to lower forms, and without this hydrochloric acid there is little digestion, as the intestine can accept this only after the change produced by the stomach.

Primary proteases and peptones are formed by this first treatment in the stomach, and in this form, a reeking mass of acid debris, it is passed into this same duodenum, or first division below the stomach, where it meets the combined secretions from the liver and pancreas, the duct end of the pancreas, where the proteases and peptones are still further reduced to serum albumens, and amino acids, and primary albumens and proteins of all sorts.

These are now absorbed through the intestinal villi, as were the starchy foods, and carried by the portal circulation to the same old liver, which has this task also of examination and censorship, rejecting or accepting as seems best.

In the circulation there is a still further reduction of the proteins into monoproteins, the most elementary forms, and at once sets in a series of reconstructive metamorphoses to bring this class into the form of our own specific tissue proteins, in which form it is either used at once for necessary reconstructive work or repair or. is also stored in the tissues for future use, the liver again being a very considerable storehouse for this class also.

Proteins are not subject to fermentation (would that they were!) but to putrefactive changes, as witness the decayed egg.

So when these residues reach the colon it will at once impress the necessity of their early removal by the active colon action, else a too long residence there will insure putrefaction.

The digestion of fats is a much more simple process, being a mere emulsification by the bile, and in this finely separated state they are absorbed directly into the general circulation, without elaboration by the liver, through the duct for that purpose, and in the form of a milky looking mixture called chyle.

Fats are stored as such in the tissues or are oxidized directly as energy just as are the other carbon foods, the carbohydrates, and next to sugars are the most directly available forms of energy generation that we have.

They are not in any sense necessary, as is generally supposed, for we make fats out of glycogen, in the absence of fatty foods, as we know from the fat condition of animals fed wholly on grasses and grains with practically no fats in their structure.

Fats do not interfere except in a mechanical way with the digestion of any other class of foods, for they require no part of the digestive process except the emulsifying qualities of the bile, so may be eaten together with any other class, only remembering that they do interfere mechanically with the digestion of everything insofar as they cover the food with impenetrable grease, as in the frying of meats in fat, thus interfering with the early attack of the gastric and intestinal juices.

Now, if you will remember this process of digestion as relates to carbohydrates and proteins it will do more to clear up the question of why one food should not be eaten with certain other foods than will any argument that could be thought out.

The starches and sugars, the carbohydrate forms of food, all require, without exception, alkalin conditions for their complete digestion, the proteins all require acid conditions for the first step in digestion, so these two opposite forms of food are never to be taken together.

After all food leaves the stomach conditions are alkalin wholly, the bile, the pancreatic juice and the intestinal juice all being alkalin in reaction, so this incompatibility exists only so far as stomach digestion is concerned, but this is vitally important, for if the starchy digestion is arrested fermentation sets in at once, and we have acid formation from this cause.

Protein digestion is carried on in an alkalin medium after this first acid bath in the stomach so can go on side by side with carbohydrate digestion in the small intestine, and if we could get the mass by this first stage of stomach digestion we would have no incompatibility in the simultaneous digestion of these two classes of foods.

So to avoid this incompatibility we must separate these at every meal, which we can do very easily by taking them at separate meals, as the starchy things at noon and the protein at night.

After the food mass reaches the colon, its last resting place in the body, nothing is left to be accomplished except to absorb from this the last vestiges of nutritive material, and it is then ready for dejection from the body.

The residence of this might seem unimportant from this stage if it were not for the opportunities for fermentation and putrefaction potential in this mass, for with our usual neglected act of chewing and insalivation there is quite apt to be raw starch in this colon, in fact this is so almost universal that observers are often found taking the ground that a certain amount of starch in the colon is normal, physiological.

Here again normals are dreadfully confused with averages, for clearly it is not normal for any part of the digestive process to be missed or neglected, and if 99% of people do show raw starch in their stools, as shown by the blue reaction of iodine, it only proves that 99% do not eat correctly, for no raw starch or sugar will ever reach the colon if the work of chewing and insalivation have been carried out as per schedule, and if the digestion of this food has not been arrested by addition of acid or protein to the meal.