BULL. U. S. B. F. 1912. 



PLATE CIV. 



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FIG. 110. Section of thyroid of dog 21 used as control for dog 16, figure 111. Received same water as dog 16 but 



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FIG. 111. Section of thyroid of dog 16. Marked enlargement of the thyroid, well developed hyperplasia as the result 

 of drinking water in which were suspended scrapings from fish troughs in which carcinoma of the thyroid in fish was 

 prevalent. X160. 



