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



PLATE XCVII. 



FIG. 96. Marked hyperplasia domesticated brook trout used as control for figure 97. Fish 1040, table ix. X86. 



FIG. 97. Fish from same lot treated by adding in continuous concentration potassium iodide in the water 1 : 5,000.000. 

 Marked regression of hyperplasia at the end of 13 days. Fish 1039, table ix. X86. 



