Bull. U. S. B. F. 1912. 



Plate C. 



Fig. 102. — Control for figure 103. Fisli 1090. tiilile Xll. X86. 



Vui. 10,^. — Doniestic.Tted brook tn^iit from the siiiiie lot ;ts fifjure VC tre.itc.I witli bichloride of mercury jiddcd b\- 

 contiuiiuus flow to the water in the proportion of 1 : .S.UOU.OUO for 12 duy.s. Disappeaniuce of hyperplasia. Marked reversion 

 to the norniBl type. Fish 1089. table xii. XS6. 



