Goitre and Iodin 



287 



number of goiters too large for wearing military collars per 

 1,000 drafted men. The amount in parts per billion of iodin 

 in drinking water is also given : 



Zone I — Goitre, 1-30. Iodin, 0.1-1. Washington, Oregon, Wyoming, Mon- 

 tana, parts of Utah, Minnesota, Wisconsin, and Michigan. 



Zone II — Goitre, 5-15. Iodin, .015-1.2. Nevada, Colorado, North Dakota, 

 Iowa, Ohio, Indiana, West Virginia, parts of California, Utah, South 

 Dakota, Minnesota, Wisconsin, Michigan, Pennsylvania. 



Zone III — Goitre, 1-5. Iodin, .06-9. Nebraska, Kansas, Missouri, Illinois, 

 Kentucky, Tennessee, parts of California, Arizona, New Mexico, South 

 Dakota, South Carolina, North Carolina, Virginia, Maryland, Pennsyl- 

 vania, New York. 



Zone IV — Goitre, 0.1. Iodin, 1.4-9.7. Texas Indian Territory, Arkansas, 

 Louisiana, Mississippi, Georgia, Alabama, Florida, parts of Arizona, New 

 Mexico, South Carolina, and a strip along the Atlantic seaboard. 



These zones run from east to west but are diverted southward 

 in the mountainous regions and northward in the Great Plains 

 area which contained a large salt lake centering in Kansas dur- 

 ing the Permian period. The goiter-free southern states were 

 submerged beneath the sea even as late as the Pliocene period. 



In order to determine the iodin in drinking water quantita- 

 tively very large samples are necessary, in fact the smallest 

 sample from Zone 1 must be at least 25 gallons; Zone II, 15 

 gallons; Zone III, 10 gallons; Zone IV, 5 gallons. Even with 

 such sized samples we often fail to find sufficient iodin for 

 strictly quantitative analysis. It is hoped that interested per- 

 sons will assist in this public health measure by forwarding 

 samples, in return for which w r e will send them the analysis. 

 Place about a teaspoonful of soda in a large dishpan, add water 

 and evaporate until the required total volume has been added 

 and reduced to about one liter, filter into a beaker and evaporate 

 to as small volume as practicable and transfer to an evaporating 

 dish; evaporate to dryness without burning; scrape out the dry 

 sample and send it to us for analysis. 



