In a considerable number of cases, however, even where dropsy is present, the diet may be with advantage more liberal than this, and small quantities of poultry, meat and fish given. The articles selected should be chosen from the point of view especially of their digestibility, and owing to a large part played by psychical influences in the digestive process much advantage may be gained by consulting the patient's wishes and tastes.
In selecting meat in cases of renal disease attention should be directed rather to the digestibility of the different varieties than to questions of whether the meat is red or white, thus mutton is preferable to beef on account of its greater digestibility. Further it is probably more important to regulate the quantity than to lay undue stress on the kind, thus patients may derive more benefit from small quantities of readily digestible red meat than from larger quantities of white meat. In the past too great stress has apparently been laid on the distinction between red and white meats. It must be also remembered that fish, although very useful in these cases as in other diseases where the digestive processes are impaired, is as a matter of fact singularly rich in nitrogenous extractives, and thus more work may be thrown on the kidneys with a diet containing large quantities of fish than with a diet consisting of a moderate quantity of meat and a considerable amount of vegetable. It is especially in cases of chronic renal disease where a high degree of anaemia is present and where little or no improvement has taken place on a milk diet that an ordinary mixed diet with moderate quantities of red meat produces the best results. Although in these cases it is advisable to order meat, the amount given should be strictly regulated and it is probably always advisable to limit the meat to once a day at the outside. Further, the practitioner must be guided by the results and should pay especial attention to the general condition of the patient as gauged by the colour of the mucous membranes and the body-weight as well as by the state of the urine. In estimating the body-weight, however, care must be taken so far as is possible to avoid the fallacies dependent on the variations in the amount of dropsy. Both the incidence and the subsidence of dropsy produce often great and sudden changes in the body-weight. Thus a sudden increase in the body-weight is much more likely to be dependent on an increase in dropsy than on an improvement in the nutrition, and similarly a sudden loss of body-weight may often be due to subsidence of the dropsy. The fact that the fluctuations in the body-weight are dependent on changes in the amount of dropsy may usually be ascertained by observing the increase or diminution in the flow of urine and also by the fact that these variations in the body-weight are much more sudden and marked than those due to an improvement in the patient's nutrition. Although a meat diet may be and often is most suitable for certain cases of chronic renal disease, there are certain forms of meat food that are highly objectionable in such cases. First and foremost great care should be taken that all meat should be absolutely fresh, as there is little doubt that very severe symptoms of a gastro-intestinal type may result from the consumption of tainted foods. An attack of gastro-enteritis which in a healthy person may give rise to only temporary discomfort may in chronic renal disease be not only very serious, but may even cause death. Gastro-enteritis would seem to be very easily produced in cases of chronic renal disease, and this complication may lead to the development of uraemia. Preserved and especially smoked, concentrated, and salted meat foods are also unsuitable in these cases inasmuch as such foods are necessarily very rich in protein constituents and thus throw an undue strain on the excretory activities of the kidneys which are impaired to a greater or less degree. It has long been recognized that smoked and salted foods are unsuitable and the observations on the influence of sodium chloride on the production of dropsy afford an explanation of one of the injurious effects that such articles of diet may have. For these reasons smoked ham, tongue, and preserved meats and fish are undesirable. Twice cooked food is also unsuitable, mainly owing to its relative indigestibility and also probably owing to the fact that such food may have undergone decomposition. Meat extracts, meat essences, soups and broths are also unsuitable, the meat extracts and essences owing to their richness in extractives and their concentrated character, meat soups and animal broths are also not advisable since their nutritive value is low and they tend to produce looseness of the bowels or even actual diarrhoea. A diet containing a moderate or small quantity of fresh meat or poultry with occasionally fish with plenty of vegetables and fruit, together with milk puddings and farinaceous food, is most suitable for many forms of chronic Bright's disease. Even in these cases the bulk of the food should undoubtedly consist of vegetables and farinaceous articles of diet provided the patient's digestion is such that he can readily deal with it.
Where there is much wasting and the general nutrition much impaired, vegetables should be if possible cooked with butter in what is often called "the French fashion".
In that form of chronic Bright's disease where dropsy is absent it is not necessary to restrict the amount of salt in the food as is so advisable in the dropsical cases, but otherwise the dietary should be on the same general lines and inasmuch as these patients are particularly prone to suffer from uraemia care should be taken that the diet is not too liberal in proteins. Further, many of these patients suffer from the effects of high tension and marked arterial degeneration, and there can be no question that a diet rich in animal food is extremely prone to increase if not to produce high tension. In such cases the animal food in the dietary should be limited as much as possible with due regard to the degree of anaemia present. Many patients with chronic renal disease have been accustomed, as it is said, to live well and to take during long years a highly nitrogenous diet. If the diet be too suddenly restricted to milk foods they experience a great loss of strength and of energy, and although it is imperative in cases where marked high tension is present, and where the other symptoms of chronic renal disease may be slight, to limit the diet, this must be done cautiously, and in many of these cases it is advisable to allow butcher's meat either once daily or two or three times a week. If symptoms of uraemia develop or if symptoms resulting from high tension become marked, the diet must be still further limited and probably in these cases it is wise to greatly diminish solid foods and to order milk in small quantities, milk puddings, stewed fruit and farinaceous foods generally. Such patients often run great, if not greater, risks from the effects of high tension than from any of the other complications associated with renal lesions.