The weak heart action, the stasis in the venous apparatus, and the slight excursive power of the thorax gradually cause in the bronchial mucosa and in the compressed lungs an extensive congestive hyper emia which in its turn gives rise to catarrhs with nearly uniformly chronic course and frequent acute exacerbations, either spontane ously or after slight irritation such as change of temperature, inspi ration of cold air, stay in damp rooms, wind, a wetting, etc. The patients cough much, expectorate continually, the breathing of any at all irritating air may produce paroxysms of cough, or the mucus accumulated in the bronchi may give rise to it. While the percus sion sound of the lung is proportionately weakened by the increasing layer of fat, we perceive in auscultation, aside from a more-or less altered, exaggerated, or diminished vesicular murmur, various small and large vesicular rides, purring and whistling sounds over larger or smaller portions of the lungs. In these ever acutely exacerbating chronic catarrhs lies the further danger to the patient of a lobular catarrhal pneumonia, as the inflammation readily extends from the bronchi to the alveoli, even by the irritation of the trickling or aspi rated mucus. Owing to the insufficiency of the heart muscle the prognosis of such pneumonias in the obese is as a rule unfavorable and a fatal termination is rather frequent.
Further results of the chronic catarrhs of the air passages, owing to the high expiratory pressure in the paroxysms of cough and to the distention of the alveoli whose bronchioles are plugged by swelling and mucus during the forced inspiration, are inflation of the lung tissue, diminution of its elasticity, and emphysema, which latter again leads to disturbances in the pulmonary circulation and adds another complication to the disease.
Influence of the Circulatory Disturbances upon the Excretion of Water by the Shin and Kidneys.—The irritability of the sweat glands and the secretion of sweat which is dependent upon heat, muscular activity, and nervous influences, is greatly increased in corpulence. The skin is congested, the sweat glands are in a state of continual irritation, and the insensible perspiration is increased. A barely appreciable rise of temperature, and the least apparent exertion, but which in the corpulent, owing to the displacement of the heavy masses of fat deposited on the body, is always associated with con siderable muscular effort and leads to increased manifestation of energy and development of heat, cause more or less-profuse sweating. The augmented excretion of water by the skin, however, is due also to another cause, namely, the lessened excretion of water by the kid neys, which becomes more and more perceptible with the increase of the circulatory disturbances and the stasis in the venous apparatus, and is followed by greater tension in the vicariously acting organs, the skin and lungs. In this stage the quantity of urine during
twenty-four hours varies between 600 and 1,500 c.c. (20 and 50 ounces), of course according to the amount of fluid ingested.
If the amounts of fluid ingested and of urine excreted during twenty four hours are carefully measured in such patients and the difference noted, most remarkable results are often obtained. Under ordinary nutritive conditions and an average amount of water in the solid food, the kidneys excrete normally, unless special causes are present for in creased excretion of water by the skin and lungs, about 18 to 30 per cent. less than the water ingested with the beverages. This differ ence, together with the water contained in the solids, passes off in the sensible and insensible perspiration. Instead of this nearly con stant difference, we obtain in these patients a deficit sometimes of 40 to 60 per cent., sometimes of only 5 to 10 per cent.—even making allowance for the perspiration or preventing it as much as possible— or sometimes a surplus in the urine of from 6 to 10 per cent. and more. Allowing in this calculation for the water normally excreted by the skin, 18 to 30 per cent., we have a surplus of 36 to 40 per cent. which can only be derived from the water accumulated in the body.
Hence quite marked irregularities in the urinary secretion are manifested, which occur in the form of polyuria and oliguria, the former of which always removes more or less completely the water left in the body by the latter. In the further course of the circula tory disturbances these relations change, but always more and more to the disadvantage of the excretion of water by the kidneys. The polyurias occur more rarely and no longer deplete the blood and the tissues sufficiently of the water accumulated in them, and the pletho ric form of corpulence gradually changes into the hydroemic.
The urine varies in concentration according to the quantity passed. When the conditions are still normal it hardly differs from the ordi nary. In oliguria it is highly colored, dark yellow, brown to dark brown, and on cooling deposits a large quantity of urates. But when polyuria occurs the coloring matter is more diluted by the large amount of excreted water and the urine appears lighter, pale yellow or almost colorless. The specific gravity depends altogether on the concentration of the urine. Of the solid constituents the quantity of urea varies according to the ingestion of nitrogen and its transforma tion in the body. The urates and uric acid are most frequently in creased and form the chief constituents of the sediment. But an excretion of large amounts of oxalic acid and even true oxaluria may be observed.