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



Plate XCIX. 



Fu;. luO. — H\brid yearling snlmoii. l^irfce protruding tiiiuor showing marked change with reversion toward normal 

 type as the result of treatment with iodine added to the water by continuous flow in the proportion of 1 : 5.000,000 for 24 

 days. Creat visible reduction in size of tumor. Fish 1083. table ix. XS6. 



:*f^. 



r;."? 



.a^.^-:- 





-.M 



v^^vie*: 



i"?^*' 



r-^^i 





.>/ *»•• 



■r 





■'as 





iL^3 



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Fig. litl.— Section through tumor retrograding as the result of treatment with potassium iodide added to the water 

 by continuous flow in a concentration of 1 : SODO.OOii, at the end of 31 days. I^arge area showing organization by connective 

 ti.ssue. previous hemorrhage in substance of tumor induced by treatment. Great reduction in size of tumor. Fish 1060. 

 table IX, X136. 



