Imagens das páginas
PDF
ePub

day and night, but the amount of urea was about one seventh less in the latter period.

The acidity is especially low in the morning.

Kaupp's experiments prove that there is a kind of antagonism between the excretion of the day and night. If the former is unusually profuse, the latter diminishes; and the reverse.

As compared with the insensible perspiration (skin and lungs), the urine was found by Gross to be comparatively less during the night, and greater in the morning.

In the "Gulstonian Lectures" for 1855,' I stated that some observations led me to believe there was a kind of periodical wave of gradual increase and decrease of urinary excretion extending over two or three days. My experiments are not yet sufficiently complete to allow of citation; but I again mention the statement here, as from an analysis of Kaupp's experiments, Professor Radiche2 has indicated an analogous fact, and Vierordt2 has also noticed a "two days' periodicity," often in an undoubted manner.

With respect to the time of year, Professor Vogel has proved by experiments, what universal observation had previously affirmed, that in the cold months, when the skin transpires little, the water of the urine increases.

The effect of heightened temperature on the urea, &c., has already been noted.

Fourcroy thought the uric acid was increased in winter. Lehmann does not confirm this; and Ranke's experiments show little difference between summer and winter.

The effect of continued cold, however, on the urine has not been perfectly investigated. The effect of diet, dress, exercise, and atmospheric conditions, must be accounted for.

Changes of season must affect the urine by alterations in temperature, and perhaps of atmospheric humidity and pressure; but it remains to be seen how far the appliances, the abundant clothing and the artificial warmth, of modern life neutralize the effect of these changes.5

1 Med. Times and Gazette.

2 Archiv für phys. Heilk., 1858, p. 207 and p. 227.

Vogel, in Wagner's Handworterbuch, 1st edit., p. 264.

Ausscheidung der Harnsaure, p. 8.

Schweig asserted that the uric acid altered with the changes of the moon, but the variations he notes are less than the errors of the method employed. See Ludwig's Phys., 1st ed., Band ii, p. 262.

SECTION XVII.

CLIMATE.

Scarcely any experiments have yet been made to show the influence of climate on the urine. The effect of temperature in the tropics would probably be analogous to its action in temperate zones; and the study of this point will doubtless throw eventual light on many of the diseases which affect Europeans on their first entrance on tropical life.

It has been affirmed by Schultens, on apparently insufficient grounds, that the uric acid is increased in Holland, where the air is very moist. A series of comparative experiments in the dry and rainy seasons of India would certainly lead to some interesting results.1

SECTION XVIII.

COMPOSITION OF THE BLOOD.

Most agencies act through the blood on the kidneys, and the composition of each fluid must be, to a considerable extent, an index of the composition of the other. At present, however, we are uncertain how far this is the case, as few comparative analyses have been made. That an excess of water or of salts in the blood leads to excess of urinary water or salts, that excess of albuminates (fibrine?) leads in most cases to excess of urea and uric acid (not by immediate oxidation, but by action on the organs?), and that any peculiar destruction of red particles is evident by a corresponding increase in urinary pigment, and a few other facts of a like kind, comprise all that is known at present,

Moslers has endeavoured to determine the relative amounts of the red particles in the blood (as counted by the method of Welcker), and of the urea and other constituents in the urine.

1 The influence of heat and cold on the skin in the production of disease among the English in India, and on invalids of the Indian service, has been well discussed by Sir Ronald Martin (Influence of Tropical Climates).

2 Hermann (Virchow's Archiv, Band xvii, p. 451) has lately contradicted the statement of Kierulf, that a great amount of water in the blood produces at once albuminuria. It never does this without local kidney injury (excessive pressure). 3 Corr. Blatt des Vereins für wiss. Heilk., No. 25.

The experiments were made on a boy, a man, and two young women. The results were indecisive, as it was impossible to compare the two cases with each other, except in the instance of the two women; the woman with the greatest amount of blood corpucles excreted more urea, pigment, and sulphuric acid than the other, but less PO, and chloride of sodium. These experiments can be considered only as the commencement of this difficult inquiry.

In animals, when a very great amount of fluid is added to the blood, bile pigment can be detected in the urine (Hermann).1 So also when the dilution reaches a very high point, hæmatin passes from the blood-cells into the serum, and then into the urine; the walls of the glomeruli being more permeable for this substance than for serum-albumen. Whether this can occur in men, from excessive water-drinking, is unknown.

SECTION XIX.

THE ACTION OF THE HEART.

The action of the heart must affect greatly both the rapidity of circulation, and the pressure on the renal vessels. That it is overruled by other agencies (nervous?) is shown by the fact that the two kidneys do not excrete with an equal rapidity, but that their action alternates to a certain extent, as if their vessels were alternately more or less contracted or dilated. For the full discussion of this difficult subject, I must refer to physiological works, and shall here merely content myself with the general statement, which seems, on the whole, to be warranted by the observations of Ludwig, Goll, Dornbluth, and Heynsius, that, other things being equal, a strongly beating heart will furnish urine more abundant in water, and richer in solids, than a feeble heart. In health, however, the effect of the varying action of the heart is certainly not very apparent.

SECTION XX.

ACTION OF THE NERVOUS SYSTEM.

The experiments of Bernard,2 Ludwig, Brown-Sequard, Schiff, and others, on dogs and rabbits have shown how remark

1 Hermann thinks this is derived from the hæmato-globulin, the hæmatin being in fact transformed into bile-pigment.

2 See especially Bernard, Leçons, Band ii, p. 153.

ably the secretions of many glands are affected by injuries and irritations of the nerves. The kidneys are no exception.

Saccharine urine is produced by irritation of the base of the brain, especially of the fourth ventricle, of the upper part of the cord, and of the sympathetic. The action of the kidneys is here merely secondary; more sugar is formed in the liver than can be destroyed, and it therefore emerges by the urine.

Albuminous urine is caused by injury of the sympathetic in the neck (Bernard); but the exact mode in which it is produced is uncertain.

Excessive flow of urinary water (diabetes insipidus) is also produced by injury of the sympathetic in the neck (Bernard), and results, perhaps, from dilatation of the renal vessels, produced by paralysis of the constrictor nerves, or by increased action of the nerves, which, in some unexplained way, causes dilatation of the vessels. The result is the same in the case of the kidney as in the salivary gland.

It is to be presumed that the nervous and excreting systems of man are governed by similar laws; and, indeed, we know that saccharine urine is sometimes produced by injuries at the base of the brain (and of the spine?). Whether albuminuria in man ever arises from disease of the nervous system, is unknown; but there are some indications that diabetes insipidus is really produced by some nervous conditions, similar, perhaps, to those caused in dogs by actual experiment. In the temporary diabetes insipidus of hysteria, epilepsy, &c., the same condition may be present, and possibly it will be found to be produced simply by altered contractility of the renal vessels.

But this subject is evidently too little advanced to permit any profitable discussion.

when

Beneke,1 from observations on himself, has noticed that when the nervous system is, so to speak, in good tone, i. e., there is a feeling of vigorous health, and when all the functions are rightly performed, the amount of urine (and of urea?) increases. On the other hand, when there is langour and depression, the urine is less in amount. The difficulty here, of course, is to define the term "tone of the nervous system.' That something real is meant, is certain; and the immediate influence on the amount of the urine of this state is, I think, put beyond doubt by Beneke's elaborate inquiry.

1 Archiv des Vereins für wiss. Heilk., Band i.

SECTION XXI.

INDIVIDUAL PECULIARITY.

If it were possible to place two individuals, of the same sex, age, and weight, under precisely equal conditions of food, exercise, rest, external temperature, &c., would the urinary excretion be the same in each person? In the same individual, the equalisation of all the conditions certainly tends to render comparatively stable the urinary excretions from day to day; but then, in the case of another person, some differences exist which cannot be done away with or compensated.

Individuals differ

First, in the comparative action of the different excretion organs; so that in one person more work is done by the kidneys, in another by the skin, or lungs, or bowels. To take one illustration from some analyses by Hegar. Two persons, on the same diet excreted of chloride of sydium the following amounts:

[merged small][ocr errors][merged small][ocr errors][merged small][merged small][ocr errors][merged small][ocr errors][merged small][merged small][ocr errors][ocr errors][ocr errors][merged small]

Either the food was very different in composition or quantity (which does not appear), or the chloride of sodium passed off, in the case of H, more copiously by the kidneys, in G by the skin.

The same is the case with the water. The phosphates again, in some persons, are probably excreted more largely by the bowels. This may be the case with the SO, as I think that rather free, healthy intestinal action lessens the urinary SO; and we know, from Marcet's observations, that sulphur passes in the stools. In the case of the urea, too, it is not at all impossible, that in some persons more may be excreted by the skin, and comparatively less by the kidneys; but the facts are not sufficient to prove this at present.

Secondly, in the metamorphosis of tissue. Thus, it seems quite clear that the amount of uric acid differs remarkably in different persons, and is not so much influenced by weight as the other ingredients. It seems almost certain that some persons naturally make more uric acid (and less urea?) than others; so that no equalisation of food and other conditions would render the urinary composition of such persons equal to that of others.

« AnteriorContinuar »