34 WILDER TILESTON 



Exogenous Obesity 



This is the ordinary form of adiposity, the Mastfettsucht of the 

 Germans, and constitutes probably ninety-nine per cent or more of the 

 cases met in practice. 



Heredity. A history of obesity in other members of the family is 

 obtained in about seventy per cent of the cases. Since, however, the 

 metabolism is normal, it is evident that the obesity is not inherited, and a 

 careful inquiry will show that family habits of eating, possibly com- 

 bined with the inheritance of a phlegmatic disposition, account for the 

 condition. 



Race. Certain races show a large incidence of obesity. This is to 

 be attributed entirely to their manner of life. 



Sex. Obesity is much more common in women, owing no doubt to 

 their less active form of life, and to the influence of repeated pregnancies, 

 during which, owing to a popular misconception, overeating is 'usually 

 encouraged. 



Age. Obesity develops most often in women during the period from 

 30 to 40 years, and in men between 40 and 50. The earlier incidence in 

 women is due mainly to the influence of child-bearing and lactation, with 

 the accompanying overeating and lack of exercise. The menopause, 

 contrary to a common belief, exerts little influence, the weight remaining 

 stationary or decreasing quite as often as it increases at this epoch. 



Less often the onset is in childhood. A not infrequent type is that 

 in which obesity develops around the age of ten years, to disappear, with- 

 out treatment, after puberty is established. 



Symptomatology. So long as the accumulation of fat is of moderate 

 proportions, no symptoms result. With a high degree of obesity, how- 

 ever, and with lesser grades in the presence of serious disease of the heart 

 and circulation, the condition is more serious. 



The Circulation. The chief danger lies in the effect on the heart. As 

 is well known, the weight of the heart is proportional, not to the body 

 weight, but to the total weight of the voluntary muscles. The heart in 

 the obese during exertion is put to a greater strain on account of the 

 greater mass to be moved, and not being as a rule hypertrophied, must 

 respond with a greater proportion of its reserve force than is normally 

 employed. With increasing weight, and decreasing muscular power owing 

 to restricted exercise, the disproportion becomes greater, until finally 

 a stage of cardiac dilatation and decompensation is reached. Contributing 

 factors are impeded motion of the diaphragm due to distention of the 

 abdomen, by fat, and in. extreme cases fatty infiltration of the cardiac 

 muscle, which may be so extensive that the contraction of the fibers is 



