THE THYROID APPARATUS 7Q 



the oblique angle of the eyelids, by the normal development of 

 the epiphyses and the centres of ossification of the short bones, 

 and more especially by the fact that the exhibition of thyroid is 

 attended by negative results. In mongolism the thyroid gland 

 is usually normal, and suppression of its function cannot be re- 

 garded as pathogenetic in this condition. Alt and Schuller are 

 of the opinion that mongolism results from an affection of the 

 sexual glands and is, in fact, a primary dysgenitalism. 



A condition resulting from thyroid insufficiency, which is of 

 far greater clinical and social significance than those which have 

 been described, is endemic cretinism. Its distribution alone makes 

 it of importance. In 1883, the number of cretins in Italy was 

 12,882, and in Austria west of the Leitha, 12,815. In France in 

 1873, there were 120,000 cretins, distributed over Savoy, the 

 Maritime Alps, and the Pyrenees. 



Endemic cretinism is characterized by clinical signs similar 

 to those which have been repeatedly described as resulting from 

 athyrosis. Of these, the most noticeable is the disturbance of 

 the processes of growth of the skeleton and soft parts, which is 

 well seen in the more or less characteristic changes which take 

 place in the face. Owing to the premature cessation of develop- 

 ment of the base of the skull, the root of the nose is broad and 

 sunken; the stature is dwarf-like; and the development of the 

 genitals remains at the infantile stage. The texture of the skin 

 and the cuticular trophic changes are similar to those of myx- 

 cedema. But the most characteristic symptoms are arrest of 

 mental development, idiocy, and disturbances of the sensorium. 

 Of the latter, deaf-mutism is the commonest manifestation. 



The thyroid gland plays an important part in endemic cre- 

 tinism, though its responsibility in this direction has been 

 variously defined. Several authors describe cases in which the 

 thyroid was absent altogether and, according to v. Wagner, this 

 occurs in 10 per cent, of the cases of typical cretinism. But this 

 finding is purely clinical, and post-mortem evidence of a thyroid- 

 aplasia, or of the total atrophy of an already developed thyroid, 

 is not as yet forthcoming. Congenital absence of the thyroid 

 comes under Pineles' definition of congenital myxcedema. As a 

 general rule, the post-mortem finding in cretinism is goitrous 

 degeneration and, more rarely, atrophy of the thyroid (v^ Eisels- 

 berg). Histological investigation shows either goitrous hyper- 

 trophy, or simple or chronic inflammatory atrophy of the thyroid 

 parenchyma, though both conditions are occasionally present in 

 the same subject. W. Scholz lays special stress upon the fact, 

 however, that in all his cases as well as in some of those of his 

 predecessors, a proportion of normal, active thyroid tissue re- 

 mained. 



Both the origin and the nature of endemic cretinism have 

 formed the subject of a multiplicity of hypotheses. As early as 



