Bull. U. S. B. F. 191 2 



Plate XCVIII. 



5 • V- - -^ 



^ « 





O' 



^^^-^^l^f^ 



TX^t 



.\Tt 





Fn;. 98. — Marked h\ perplasia domesticated brook trout used as control for figure 99. Fish 1070. table ix. X86. 



Fig. 99. — Fish from same lot treated b.v adding in cnitimiuus concentration potassium iodide in the water 1 : 5,000.000. 

 Marked regre-S.sion of hyperplasia at the end of 27 days. Fish lii69. table ix. XS6. 



