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



PLATE C. 



*~ 



FIG. 102. Control for figure 103. Fish 1090. table xn. XS6. 



FIG. 103. Domesticated brook trout from the same lot as figure 102. treated with bichloride of mercury added by 

 continuous flow to the water in the proportion of 1 : 5.000.000 for 12 days. Disappearance of hyperplasia. Marked reversion 

 to the normal type. Fish 1089. table xn. XS6. 



