The causation of chronic rheumatism is not exactly known. Our present knowledge indicates that an important factor in rheumatism is a poisoning of the system by a poison absorbed from a latent catarrh, such as is frequently present in the digestive tract, uterus, bladder, or other mucous membrane (see Auto-intoxication). In the presence of a weak spot of this kind, diet frequently acts as an exciting cause. It may do so in virtue of one or other of the following defects: -

1. Excess of animal protein foods, such as is involved in taking a rich meat diet twice or thrice daily, with a resulting excessive putrefaction of proteins.

2. Excess of sugars, jams, etc., such as is involved in taking four or five cups of tea daily with much sugar, also marmalade and jams, sweets and chocolate, with abnormal fermentations as a sequel. The careful application to the urine of the test known as the pancreatic reaction (p. 377) is of great value as indicating whether there is any excess of farinaceous or saccharine foods.

3. Excess Of Fruits

An excess in either of these directions may induce all the symptoms of chronic rheumatism. In a few cases the patient is aware that certain articles of diet induce his rheumatism, and under these circumstances the use of such foods or drinks should be avoided or restricted. There is no question that some rheumatic subjects keep themselves free from pain on a lacto-vegetarian diet (p. 520). No hard and fast rules can be laid down. In the investigation of rheumatic cases, careful attention must be directed to the dietary of the patient for a long time prior to the development of rheumatic symptoms. Has the patient indulged too freely in animal "protein foods"? e.g., indulging in a rich red-meat diet twice or thrice daily. Has he been in the habit of taking a large amount of sugar, in the form of sugar in his tea, jam, fruit, and the like? Has he partaken of beer or other alcoholic liquors to an extent which is prejudicial to him? e.g., taking a little of beer daily to lunch over a lengthened period, when leading a comparatively sedentary life. And lastly, has there been in operation any contributory factor, such as constipation, the existence of which would be an important contributing factor?

Most cases of rheumatism can be cured by these points. In conclusion one may formulate the general rules: -

1. The diet should be a simple one, taken a intervals, and eaten slowly. When the digestion is good and the appetite strong, a large amount of food may be taken provided it be of a simple nature. Special care must be taken to prevent constipation.

2. Any article of food or drink which the patients have good reason to believe detrimental should be withheld or taken in sparing amount. Their nature frequently gives a clue to the nature of the faulty metabolism present. In this connection it is important to note the periodic nature of the symptoms, e.g. recurrence of "rheumatism " at the fruit season.

3. More Fluid Should Be Taken

Most rheumatic subjects drink too little. The writer has had under his care a lady affected with chronic rheumatic pains who passed only from 6 to 8 ounces of urine daily. Similar cases are far from uncommon. Plain water, hot water night and morning, or Lithia water, to the extent of about 15 to 20 ounces (two tumblerfuls) should be taken daily, on an empty stomach.

4. If the patient can furnish no clue as to dietetic error, and if the pancreatic reaction of the urine is of a negative character, the best plan is as follows: - (a) Reduce the diet, making it as simple as possible, and if that does not suffice, cut off meat foods, putting the patient on a lacto-vegetarian diet, care being at the same time taken that no excess of sugar is taken in the dietary. Special value in some cases attaches to the use of buttermilk, of which a detailed account is given on p. 540.