Thomas. — Effects of Certain Oils Upon Brook Trout 127 



Levy* notes that fish are reported to be affected by sulphite 

 liquor wastes from paper mills. It is said that when the waste is 

 emptied into streams, where fish are usually caught, the fish will 

 not bite, but if the pollution is stopped for a period, good catches 

 are made until the stream is again polluted. This Dr. Levy points 

 out would tend to show that the fish were present all the time but 

 refused to bite in the polluted water. 



During the experiments it was noted that the fish would not 

 feed in solutions of the sulphite liquor, but if taken from them 

 and placed in pure water at intervals for a few minutes they would 

 eat ravenously. Though this waste may not be termed toxic in 

 the strictest sense, the fish certainly do not thrive in it. The 

 evidence gathered shows that washings from roads treated with 

 this substance, though they would not kill the fish perhaps, would 

 tend to drive them to another locality free from pollution. 



Water gas tar proved extremely toxic. A sample obtained 

 from Providence, R. I., killed trout in thirty hours at a concen- 

 tration of two and a half parts per million. In several cases the 

 fish behaved not unlike they did in water to which creosote has 

 been added. This behavior will be mentioned later. 



A sample of light fuel oil was obtained from the Division of 

 Fly and Mosquito Suppression of the Brookline, (Mass.), Board 

 of Health. This oil is used to destroy and prevent mosquito larvae 

 in pools and the like. The oil was found to be non toxic. It emul- 

 sified upon aeration as did the sample of oil No. 5899 from the 

 Office of Public Roads. After the oil had reached this state it 

 coated the gill membranes. In experiments where the water was 

 not aerated no emulsification took place and the fish appeared to 

 be in a perfectly healthy state and would feed regularly. No signs 

 of distress were shown at any time provided the water was renewed 

 often enough to prevent asphyxiation. 



Creosotes are used extensively as preservatives for wood that 

 is to be immersed in water. Fishing nets are also "cured" at 

 times by means of creosote. An article on "Net Curing by 

 Creosote" appeared in the Fish Trades Gazette,^ in which attention 



* Levy, E. C; Report to the Water Committee in the Investigation 

 of the Effect of Trades Wastes on the Waters of the James River at Rich- 

 mond, 1905. 



t Fish Trades Gazette (London) vol. xxxl, No. 1606, Feb. 28th, 1914. 



