OBESITY 37 



dolorosa occupies a doubtful position. Border-line cases are not infre- 

 quent, and are difficult to classify, as emphasized by Lyon, who discusses 

 the whole question at length. 



(1) Circumscribed nodular lipomatosis. This condition is character- 

 ized by the presence of lipomata of the ordinary variety. Though it may be 

 associated with the rarer types of obesity and lipomatosis, it is so common 

 apart from these that there is probably no causal connection, and it should 

 therefore be classified with the benign tumors. 



(2) Diffuse symmetrical lipomatosis. This form differs from the 

 preceding in that it is chiefly confined to males, while the ordinary lipoma 

 is much more common among women, and in the fact that the fatty masses 

 are seldom encapsulated. The fatty deposits are most commonly situated 

 in the neck, constituting the "fatty neck" of Madelung, but are some- 

 times symmetrically placed on the trunk and extremities, especially in 

 relation to the muscles, and always to the exclusion of the face, hands and 

 feet. The etiology is obscure. 



(3) Lipodystrophia progressive. This exceedingly rare disease is 

 characterized by a progressive and profound atrophy of the fatty tissues 

 of the face and upper part of the body, often associated with fat deposit 

 about the buttocks and thighs. The cause is unknown. 



Endogenous Obesity 



Endogenous obesity may be defined as obesity dependent upon dis- 

 ordered function of one or more of the endocrin glands. It is rare in 

 comparison with the ordinary form. 



(1) Thyrogenous Obesity. The thyroid gland is usually more or 

 less enlarged, but in the absence of histological examinations little more 

 can be said. The obesity usually sets in early in life, and may be due 

 to inherited tendencies. It is very resistant to diet, but yields to thyroid 

 therapy. Occasionally obesity develops in connection with thyroiditis, 

 especially after the acute infectious diseases, and in syphilis. Lesser 

 grades of thyroid insufficiency are accompanied by a basal metabolism 

 which is within normal limits. In such cases exogenous factors are often 

 at work (overeating, etc.), and hypof unction of the thyroid may merely 

 create a predisposition. In a few instances a well-marked lowering of 

 the basal metabolism has been demonstrated ; these cases are distinguished 

 from myxedema by the lack of the usual symptoms of the latter condition, 

 and by the fact that fat, not mucin, is deposited. 



(2) Obesity of Hypophyseal Origin. Frohlich was the first, in 

 1901, to call attention to the association of obesity of a peculiar form 

 and dysgenitalism with a lesion of the pituitary. The discovery that 

 these changes are due to diminished functioning of the gland, or hypo- 



