THE THYROID APPARATUS 8 1 



gland. As the latter factor develops under the influence of the 

 former, a distinct clinical type is evolved, which is to be regarded 

 as the resultant of both the operating causes." 



There is undoubtedly a close etiological relationship between 

 endemic cretinism and endemic goitre. Virchow pointed out that 

 " true endemic cretinism always appears in goitre areas, and we 

 do not know of a single spot on the inhabited earth where true 

 endemic cretinism occurs which is not also the seat of endemic 

 goitre." In addition to this territorial relationship, there is a 

 large number of facts which point to a close etiological connection 

 between the two conditions. The most suggestive of these is the 

 fact, mentioned by Fodere in 1800 and since repeatedly confirmed, 

 that in the greater number of instances of cretinism, the parents 

 are either cretinous or goitrous, but that goitre is invariably 

 present in the antecedents. From these observations Fodere con- 

 cluded that goitre was the first stage of a degenerative process, 

 the last stage of which was cretinism. This view is supported by 

 the large majority of observers, and is now very generally 

 accepted. 



The results of recent investigations supply certain factors of 

 indisputable importance in the etiology of endemic goitre and 

 endemic cretinism. The occurrence of both conditions is confined 

 to specific localities. These are the higher mountainous districts 

 in Europe, more particularly the region of the Central Alps; 

 in Asia, the Himalayas; in Central America, the Cordilleras; in 

 Africa, all the mountainous regions. A comparison of the con- 

 ditions shows that the distribution of these endemics is dependent 

 neither upon climatic nor meteorological factors, but upon the 

 composition of the soil. Bircher's investigations led him to con- 

 clude that endemic goitre and cretinous degeneration occur only 

 upon the marine deposits of the Palaeozoic (Devonian, Silurian, 

 coal, dyas), Triassic and Tertiary periods ; while the crystalline 

 formations of volcanic origin of the Archaean period, the sedi- 

 mentary deposits of the Triassic, Cretaceous and Quaternary 

 periods, as well as all fresh-water deposits, are free from goitre. 

 Kocher found that this classification required a certain amount 

 of modification, but he agrees with Bircher that the causal factor 

 lies, not in the mineralogical composition of the soil, nor in the 

 chemical composition of the rocks, but in a certain definite con- 

 tamination inherent in the soil, as the result of its geological 

 formation. The direct causative agent of goitre and cretinism is 

 water, derived from certain geological formations, and rendered 

 impure by specific by-admixtures. 



The etiological importance of drinking-water cannot be 

 doubted when we remember that goitre may be developed in a 

 short time by drinking from so-called "goitre springs"; while, 

 on the other hand, even in districts where goitre is endemic, 

 persons who refrain from drinking the "goitre water" are free 



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