THE CRETINIC DEGENERATION 455 



soldiers and inhabitants who dwelt in this better environment escaped 

 the disease. 



Kutschera, Taussig and others have made important contributions in 

 emphasizing the probability of a direct contagion as the etiologic agent of 

 cretinic degeneration but tend to obscure the issue somewhat by under- 

 valuing the importance of water as a common mode of infection. 



The Bacterial Theory. A further and perhaps final step in the de- 

 velopment of our knowledge of the etiology of cretinic degeneration has 

 been made by Major R. McCarrison (d) of the Indian Medical Service 

 whose studies of the disease have extended over a deeennium in India as 

 well as including visits to the European endemic areas. His writings have 

 been collected in the Milroy Lectures in the Lancet, 1913, and his mono- 

 graphs, "The Etiology of Endemic Goiter,'' 1913, and "The Thyroid 

 Gland/' 1917. Perhaps it is due to the remote country in which McCar- 

 rison's important researches were carried out that they have not been as 

 largely disseminated in the literature and in the scientific medical world 

 as they would otherwise have been. McCarrison believes that cretinic de- 

 generation is usually due to fecal bacteria or their toxins emanating from 

 the alimentary canal of man. Though fully appreciating that water is the 

 chief mode of infection, he likewise ascribes due importance to direct 

 contact, house and soil infection. McCarrison bases his theory upon his 

 personal observations on endemicity in India, his experimental production 

 of goiter in man and animals by goitrigenous water, and by water con- 

 taminated by feces of goitrous and cretinous individuals; also upon similar 

 animal and, fish experiments by Bircher, Gaylord, Marine and Lenhart 

 et al. 



McCarrison's experimental production of goiter in man is of particular 

 significance as it took place by the fifteenth day, reaching full develop- 

 ment within a month. The relatively short latent period thus observed 

 seems to remove one of the greatest obstacles to acceptance of the infec- 

 tious theory of goiter on the part of the older authorities, who maintained 

 the disease could not be bacterial on account of the long exposure neces- 

 sary for its development. 



Particularly convincing are the experiments in which fecal bacteria 

 from goitrous individuals were fed pregnant goats who gave birth to cretin 

 kids with large congenital goiters. Goiters were similarly produced in 

 rats. The anerobic intestinal flora were most marked in their goitrigenous 

 action. 



McCarrison explains the frequency of cretinic degeneration in rural 

 districts by the lack of hygiene and sanitation in these regions, its prev- 

 alence in mountainous and hilly regions by the greater possibility of sur- 

 face contamination of the water supply through torrential waterfall, the 

 declivity of the terrain, and lack of water supply protected by aqueducts, 

 etc. The geological condition of the land is only of importance on ac- 



