BULL U. S. B. F. 1912. 



PLATE CIII. 



,.- 1( - ion Section through tumor of two-year old brook trout treated with bichloride of mercury added by continuous 

 flow to the water in proportion of 1:5.000.000. Result at the end of 11 days. Great reduction in size of tumor. Reversic 

 of tumor tissue to the normal type. Fish 1144. table xn. X86. 



r*' 

 \T*&V 



JSP* 



**& 



r ., ..^,_- ,,-'-yVt, ttptMilt'A,- 



i ?.:.* ."iss/ssr^^Krs^ 



Jf^^p*^^ v*s .>-:> 



p, G i(j9 Domesticated brook .rout. Visible tumor. Marked diminution in size of the tumor and ma 

 tumor tissue with reversion toward normal, as the result of treating for 22 days with arsenic trioxide added 

 flow to the water. Note marked change in epithelium. Fish 2036. table xiv. X86. 



rked chanKe in 

 by contm 



