76 THE THYROID AND 



Kropfbrunnen, at which young men anxious to 

 escape conscription drink. They have been known 

 for centuries, and the water will induce goitre in 

 horses and dogs, as weU as in man. Boiling the 

 water destroys its remarkable effect on the thyroid 

 gland. This has been taken to prove that some 

 living organism is the effective cause, but another 

 theory is more probable, as we shall see later. 



During Captain Cook's voyage in 1772, it is related 

 that the crew ran short of water, and had recourse to 

 blocks of ice from the icebergs amongst which they 

 were sailing, melting them in iron pots. Quite a 

 number of those who partook of this water developed 

 a goitre, other members of the crew escaping. 



A large projecting swelling of the thyroid is not 

 uncommon in trout kept in certain tanks or streams. 



In the earlier stages, parenchymatous goitre can 

 usually be cured, either by feeding on thyroid extract 

 or by means of potassium iodide. Marine* has 

 pointed out that in America there was formerly a 

 serious commercial loss in some districts from cretin 

 lambs, and that sheep and dogs with goitre were 

 numerous ; the substitution of an iodiferous salt 

 for pure rock-salt has been completely successful 

 in preventing all these manifestations. 



Chalmers Watson, and more recently Edmunds, 

 have obtained goitre in fowls by a meat diet. The 

 low iodine-content of the meat makes it necessary 

 for the thyroid to enlarge, so as to take the greatest 

 advantage of what iodine it can get. 



* Johns Hopkins Hosp. Bull., 1907, xviii, p. 359. 



