410 



3- Fishes iisimlly react positively to the compounds and mixtures 

 studied; i.e., enter the polkited water from the pure water readily and 

 turn back into the polluted water when pure water is encountered. 

 The danger to fishes is increased greatly thereby. Fishes often de- 

 velop a "preference" for the polluted water after a number of trials 

 of both kinds. (P. 397.) 



4. On account of the extreme toxicity of gases such as CO and 

 ethylene, and of benzene and other volatile matter, water which has 

 been in contact with gases should not be introduced into streams. 

 (See Article VII, also pp. 395 and 409.) 



5. Various types of manufacturing and by-product recovering 

 plants, while they remove different substances do not leave a harmless 

 residue ; on account of the fact that the very toxic substances such as 

 carbon monoxide, benzene, and naphthalene differ widely in their prop- 

 erties, residues from all such plants will be almost certain to be toxic. 



(P- 395-) 



6. The results thus far obtained may throw some light on the 



poisonous effect of the various compounds from the pharmaceutical 

 standpoint, and may be of assistance in the matter of standardization 

 of drugs with fishes, 



IX. Acknowledgments. 



The writer is indebted to the State Water Survey for analyses of 

 water made at the beginning of his work. He is further much in- 

 debted to various members of the Department of Chemistry of the 

 University of Illinois, particularly to Dr. C. G. Derick, now of the 

 Research Laboratory of the Schoellkopf Aniline and Chemical Works, 

 Inc., Dr. H. J. Broderson, and Dr. G. D. Beal, for extended advice 

 and suitable chemicals. 



X. Literature consulted. 



Beacall, T., Seibert, F. M., and Robertson, I. W. 



'15. Dyestuffs and coal-tar products, their chemistry, manufac- 

 ture, and application. Crosby Lockwood and Son, London. 



Birge, E. A., and Juday, Chancey. 



'04. The inland lakes of Wisconsin. The dissolved gases of the 

 water and their biological significance. Bull. Wis. Geol. and 

 Nat. Hist. Surv., No. XXII; Sci. Ser., No. 7. 



Burrell, Geo., and others. 



'14. Relative effects of carbon monoxid on small animals. Dept. 

 Interior. Bur. Mines, Tech. Paper No. 62. 



