DISEASES OF THE GENITOURINARY ORGANS, account of the difficulty of collecting the urine in very young children, it is seldom possible to estimate the average quantity passed in the twenty four hours. It is not always easy to obtain the quantity necessary for ex amination of its chemical characters.
In health, the water is clear, light-coloured, and of low specific gravity ; but it is subject to frequent variations on account of the readiness with which the child responds to every disturbing agency. The quantity secreted is dependent upon certain conditions, such as :—The degree of blood-press ure in the renal arteries ; the facility with which the urinary tubules dis charge their contents ; and the state of the nervous system generally. Also upon the condition of the other emunctories of the body, the quantity of fluid taken, and lastly, upon the state of health of the individual. Con sequently the water pasSed varies greatly in amount. Sudden copious se cretion may be a temporary symptom in many cases of digestive derange ment ; in particular, attacks of severe abdominal pain are often terminated by a copious flow of almost colourless urine from the bladder. Also, an epileptic seizure, an attack of ague, or a fit of convulsions in the child may be followed by a profuse secretion of limpid urine. Various articles of food seem to have a direct action in promoting secretion from the kidneys. In some children barley-water has this effect ; and the nurse complains that while taking it, the child is almost " constantly wet." Again, certain diseases are accompanied by an increased flow of urine. Diabetes mellitus, and diabetes insipidus are in rare cases seen in children. The former, however, uncommon at any age under puberty, is almost unknown under five years of age. The latter is sometimes an accompaniment of gastroin testinal disorders, but ceases usually when the digestive organs have been put into a better condition.
Diminution in the quantity of water passed is the result of many dif ferent causes, and usually attracts more attention than the opposite condi tion. The skin in some children acts very freely ; and in warm weather a large proportion of the fluid may leave the body by this channel. In such
a case the urine may be very scanty. One morning in July a child aged ten months was brought to me on account of the small quantity of urine she was passing. During the preceding twenty-four hours she had passed water but once, and then in very small quantity on the evening before the visit. The weather was very warm, and the child perspired profusely, but except for slight costiveness was and seemed perfectly well. I quieted the alarm of the mother, advised that the child should be given plenty of fluid, and ordered a gentle aperient to relieve the bowels. After this, the mother was soon made happy by seeing a more copious secretion of urine. The amount of water is also diminished by diarrhoea and vomiting, which de rangements, as in the preceding case, divert a certain quantity of water from the kidneys. When the reduced secretion is due to a watery flow from the bowels, it may be unnoticed by the attendants ; but when the symptom is an accompaniment of vomiting, the small quantity of water passed from the bladder is often a cause of anxiety. In cases of extreme prostration from deficient nourishment in infants, the secretion of urine is scanty and may be completely suppressed. Indeed, Dr. Parrot attributes the cerebral symptoms which sometimes occur in such cases, and are called "spurious hydrocephalus," to toxic causes, the blood being charged with excrementi tious matters which it cannot get rid of. In the febrile state, the urinary water is diminished in quantity, and is increased again as the temperature subsides. There is, however, no reduction in the solid constituents of the urine, and the specific gravity is consequently raised. Besides the above causes which act through the system generally, other and local causes which interfere with the secreting function of the kidneys may have the same result. Thus, congestion of the kidneys from disease of the heart or liver, and Bright's disease, may reduce the quantity of water to a very small amount.