10 THE THYROID AND 



evidently containing a deficiency of iodine derived from 

 the maternal thyroid. Of 2,333 cases of congenital 

 goitre collected by Fabre and Thevenot,* the mother 

 was almost invariably goitrous. The foetal thyroid 

 enlarges in order to obtain as much iodine as it can. 



It was natural to suggest that the waters of the 

 Kropfbrunnen were deficient in iodine, but this 

 theory would overlook the fact that the bulk of our 

 iodine is derived from vegetables, not from drinking- 

 water, and as a matter of fact these wells show no 

 constant deficiency or excess of iodine. It is more 

 probable that they contain minute traces of some 

 metal having a great affinity for iodine, and forming 

 with it an insoluble compound. It is quite conceiv- 

 able that boiling the water might precipitate such 

 a metal. There are probably many metals, known 

 and unknown, that would fulfil the conditions ; it 

 wiil suffice to mention silver as an illustration. This, 

 if taken into the body, would withdraw so much of the 

 available iodine as inert silver iodide, that the thyroid 

 must enlarge to obtain the indispensable minimum. 



The theory has been advanced that the Kropf- 

 brunnen contain some organism capable of causing 

 a goitre. To accept this, however, is to overlook 

 the weight of evidence bearing on iodine metabolism 

 in relation to the thyroid. Again, it is quite in 

 accordance with the common laws of Nature to find 

 a metal or mineral specially limited to particular 

 geological formations in widely separated areas ; 

 but there is no evidence that bacteria are dependent 



* Revue de Chirurgie, June 10, 1908. 



