304 ILLINOIS STATE ACADEMY OF SCIENCE 



fall of 1922. This gland tends to enlarge daring adoles- 

 cence, but as this swelling seems to be influenced by the 

 locality from which the individual comes, a particular age 

 is not the important factor responsible for the increased 

 size of the thyroid observed. It has been known for a 

 number of years that in certain regions of the world 

 swelling of the thyroid gland was common, and it has 

 been known for a century or more that in America this 

 enlargement is pre-eminently a disease of the Great 

 Lakes' Basin, and its greatest incidence corresponds 

 rather well with that of the hard waters of the Niagara 

 limestone. It is only comparatively recently, however, 

 that this enlargement of the neck was known to occur so 

 extensively in this region and to be common in men, al- 

 though much less frequent than in women. 



Goiter is a disease usually characterized by the enlarge- 

 ment of the thyroid gland which occupies the lower por- 

 tion of the neck, anterior-laterally. There are two forms 

 of this disorder; simple goiter which is primarily a 

 swelling of this gland, and exophthalmic goiter, an en- 

 larged thyroid accompanied by a distention of the eye- 

 balls, anemia, overactivity of the heart, tremor, muscle 

 weakness, mental irritability, and general organic dis- 

 turbance. 



In the three groups of men and women examined in the 

 falls of 1920-21-22 simple enlargement of the thyroid 

 gland was found to be a health problem of importance 

 in this state. As it is due apparently to iodine insuffi- 

 ciency, it is preventable by the administration of this ele- 

 ment, either through such foods as cereals, beets, pota- 

 toes, and sea-water salt, or of iodine or its compounds. 

 Prevention of goiter reduces the death rate, increases 

 resistance of the individual to disease, improves his eco- 

 nomic status, and promotes his mental, moral, and physi- 

 cal efficiency. 



HEAKT DISEASE 



If the hearts of individuals of high school age are care- 

 fully auscultated both in the erect and recumbent posi- 

 tion and before and after exercise, definite murmurs that 

 are not cardio-respiratory in origin may be heard in from 



