Even marked degrees of acute fatty metamorphosis of the heart cannot be diagnosed during life, because the fatty change does not materially influence the function of the heart, nor does it pro duce any striking cardiac symptoms. The working capacity of the acutely de generated heart suffers but little, and the fatty organ is capable of responding like the normal heart, both to ordinary and to increased demands. It is not war ranted to attribute the frequently ob served attacks of cardiac depression to fatty degeneration of the heart-muscle. In the vast majority of cases the fatty change is a consequence, and not a cause. of loss of compensation. Hasenfeld and Fenyvessy (Berliner klin. Woch., Feb. 13, '99).
The urine of 990 obese patients exam ined, and sugar found present in 10 per cent. of that number. The percentage of diabetics seems to increase with the degree of obesity. Wollner (Berliner klin. Woch., Jan. 2S, 1901).
Certain points of distinction will be found in the division on fatty degenera tion (ride infra).
Etiology.—The chief etiological factor is general corpulency. Among condi tions predisposing to fat-production may be mentioned: (a) heredity: in about 50 per cent. of the cases of obesity the tendency is inherited, and in these the abnormal accumulation of fat shows it self quite early in life. (b) Climate: cor pulence occurs with frequency among the inhabitants of hot, moist countries, and of low countries of the temperate and arctic regions. (c) Habit and occupation: the sedentary habits of the rest-loving, phlegmatic temperament predisposes to fat-increase, while all sedentary occupations act in a similar manner. (d) Race: Jews are par ticularly subject to obesity, and the same may be said of races inhabiting certain hot, moist climates (vide supra); e.g., southern Italians, South-Pacific Island ers, and certain African peoples. (e) Age and sex: acquired obesity most frequently arises in persons of advanced middle life, between 40 and 50 years, while the con genital form is seen in infancy and child hood. The fat-heart is never found in infancy (Cutler). Corpulency is more frequent among women (particularly Jewesses) than among men, and in the former sex it often appears at puberty and between the thirtieth and fortieth years. (f) Certain diseases and condi tions may predispose (anaemia, para plegia, and loss of blood and other fluids).
It is not absolutely necessary that tu berculosis in man be associated with loss of flesh. Virulent tubercle bacilli cannot only live for years in apparent robust health, but they may in addition very much increase their adipose tissue.
Queyrat (Gaz. des Hop., No. 87, '97).
Apart from idiosyncrasy, deficient lung-capacity is, perhaps, the most fre quent cause of overfatness. Editorial (The Dietetic and Hygienic Gazette, Jan., '9S).
(g) Congenital anomalies and mon strosities (idiots, cretins, acephali).
The exciting causes may be tabulated as follows: 1. Inebriety; the intemper ate use of alcoholic beverages, especially in the form of beer, ale, porter, and the like. 2. Ingestion of fat-making food in excess. Excessive use of fats, starches, and sugars, although the too free indul gence in proteids may also be responsible, especially with insufficient physical exer cise. 3. The prolonged use of arsenic may sometimes lead to corpulence.
Practically all of the experimental evi dence in favor of the origin of fat from proteids, either physiologically or patho logically, is based on false premises. Neither a physiological nor a patho logical formation of fats out of proteids has ever been demonstrated, although the possibility of its occurrence cannot be absolutely denied. The weight of evi dence at the present day is in favor of infiltration or the formation of fat from carbohydrates. A. E. Taylor (Amer. Jour. Med. Sciences, May, '99).
Pathology.—The characteristic change consists in an abnormal deposit of fat, more especially in places where this tis sue-element is normally found, as the aurico-ventricular grooves, near to the apex, and about the great vessels at the base. This overproduction of fat is pres ent in every obese person, and when ex cessive may form an enveloping mantle, first covering the right ventricle, later the left also, attaining a diameter of an inch or more. The surface of the fat heart generally presents a pale-yellow hue, but may be a deep-yellow color, re sembling sulphur. The intermuscular fibrous tissue, as may be seen on section, is the seat also of increased accumulation of fat. In extreme cases the muscular fibres undergo atrophy, thus becoming weakened, from inordinate pressure.
Dilatation often supervenes, and it is quite probable that the symptoms, when present, are dependent upon, and date from the time of, its occurrence. Rupt ure of the organ is also not unlikely. A coronary artery and the aortic arch are often arteriosclerotic. In the cachexias of carcinoma and phthisis, the general atrophy of the aged, fatty infiltration and fatty degeneration co-exist.