DUCTLESS GLANDS TAYLOR 701 



erally accepted answer to these questions was that the drinking water 

 was at fault. Even as late as 1910 Sir Hector Mackenzie, a pioneer 

 in this field, wrote, " the most potent cause is the water used for 

 drinking purposes." He admitted that the particular something in 

 the water which affected the thyroid in this way was unknown. 

 Later, however, it was thought to be an infecting organism. 

 (McCarrison.) 



Without going further into detail I may say that the question has 

 at last been settled. It is not due to something in the water that 

 should not be there but to something that is not there which should 

 be there, if I may so express it. It is due to a dearth of iodine in 

 water and food. For this knowledge we are indebted to Marine, of 

 Qeveland, who showed a few years ago that thyroid disease in 

 brook trout could be cured by the addition of minute amounts of 

 iodine to the water in which they swam. 



That explains why cretins are practically never seen on the sea- 

 coast. The sea is an inexhaustible storehouse for iodine, which finds 

 its way into the food and the drinking water of the coast's inhabi- 

 tants. It is always in inland territories that thyroid deficiency is 

 seen, particularly in the mountains and the highlands, since they, as a 

 rule, are farther removed from the iodine supplies. Analyses of 

 the soils of goitrous districts have shown a marked scarcity of iodine. 

 Chatin, a Swiss, pointed this out 75 years ago, but no attention was 

 paid to the observation. 



The thyroid must have iodine in order to manufacture its secre- 

 tion. Without this element it struggles on as best it can, but it 

 can not make bricks without straw. It becomes enlarged, yet the 

 enlargement is made up, to a large extent, of worthless tissue with 

 its spaces filled with an impotent fluid. The important glandular 

 tissue has degenerated, and though the gland is of greater bulk it is 

 a fraud and is quite incapable of manufacturing an active secretion. 

 We wou,ld also find that such a gland was almost barren of iodine, 

 or at any rate held but a fraction of the normal amount. It is now 

 an axiom of thyroid pathology that the larger the gland the less is 

 the iodine which it contains. 



This is the usual way in which cretinism occurs, following goiter, 

 which destroys the functional activity of the gland. But in rare 

 instances thyroid function may be destroyed by some acute disease 

 of childhood, or rarer stilf, some unlucky individual may be born 

 without one. 



A similar condition, and one having the same cause, may arise in 

 adult life. It is known as myxedema and is essentially the same as 

 cretinism. There can, of course, be no stunting of the stature or 

 maldevelopment of the bones, since it appears after the period of 



