452 KELSON W. JANKEY 



There were many cretins and deaf-mutes previous to 1885 who gradually 

 disappeared* in the years succeeding the introduction of the pure water 



supply. 



As another striking instance of the influence of the water supply can 

 be quoted John W. McClelland's report of an endemic in Deoba, India. 

 The Brahmins or highest caste of the population obtained their drinking 

 water from a distant spring of high purity. They were entirely free from 

 the prevailing goiter endemic. The middle class (Kajputs) drank partly 

 good and partly goitrigenous water. Two-thirds of this class were goitrous. 

 The lowest class (Domes), who depended for their entire water supply upon 

 the local goitrigenous springs, all acquired thyroid hypertrophy. 



The noxus collects in the sediment of reservoirs while the supernatant 

 water may be innocuous. An interesting example of this action is given 

 by Thea for the town of Cuneo in Italy. The population was goiter- 

 free. It secured its water supply from the upper part of the last basin 

 of a system of reservoirs. Of the garrison, 40 per cent became goitrous 

 during a period of 8 years. It was found that the soldiers were drinking 

 unsedimented water. On obtaining their supply in the identical fashion 

 from the general town system, the goiter epidemic disappeared. 



The Chemical Hypotheses. The intimate relationship between the 

 development of endemic cretinism and the water supply has become the 

 common basis for several widely divergent etiologic theories. Thus the 

 disease was at first attributed to chemical constituents of the water. Grange 

 considered magnesium, St. Lager iron and copper pyrites, McClelland 

 and others, calcium salts as the special causative factors. Even iodin, 

 now known to be a curative agent, dissolved air, carbon dioxid, etc., have 

 been considered in this regard. Further investigation has, however, al- 

 ways disproved these hypotheses. The goitrigenous quality of water does 

 not in general depend upon the mineral content. Hard waters may lead 

 to increase in size of goiters, but this is only to be regarded in the light of 

 a predisposing etiologic factor. 



The Hydrotelluric Theory, though already advanced by many, received 

 its greatest support from II. Bircher in his important monograph on 

 "Endemic Goiter" published in 1883. Bircher concludes that : 



1. Goiter oocnrs only upon marine deposits and those especially 

 upon marine sediments of the Paleozoic, Triassic and Tertiary periods. 

 The remains of the extinct flora and fauna of these geologic ages are 

 regarded as the ultimate cause of the disease. 



That the eruptive rocks, the crystalline rocks of the Archean 

 period, the sediments of the Jurassic, Cretaceous, and Quaternary seas 

 nnd all fresh water dej>osils are free, from goiter. The mountainous en- 

 demicity is explained by the protrusion in such districts of rocks of the first 

 description. 



