Article VI. — An Experimental Study of the Effects of Gas 

 IVaste upon Fishes, zcith Especial Reference to Stream Pollution. 

 By \^ictor E. Shelford. 



I. Introduction. 



The products of destructive distillation of coal include an innum- 

 erable series of substances representing most of the important groups 

 of organic compounds ranging from gases to solids. In the manu- 

 facture of illuminating gas all these substances are thrown into 

 streams in varying amounts, depending upon the manner of treating 

 bv-products. The gases and volatile products are in solution in water 

 used in washing the gas, and are often introduced into waterways. 

 By-products, except the heavy tars, are often thrown away. This is 

 especiallv true in the case of the smaller plants where the quantitv is 

 insufficient to make the further treatment of it profitable. Thus in 

 manv plants only the heavy tars are saved, the gas liquor drip from 

 the mains and holders being dumped into waterways without the re- 

 moval of even ammonia. The immense commercial value of these 

 wasted products has been more generally appreciated since the out- 

 break of the European war, which cut off the large supply of foreign 

 dyes and important organic compounds and increased the demand for 

 such products as may be used in the manufacture of explosives. The 

 value of these wasted products should be sufficient to prevent their 

 wastage, but their injurious effect upon fishes and other life of streams 

 generally is itself sufficient to justify the prohibition of pollution by 

 this means. 



II. Statement of the Fish and Gas-waste Pollution Problem. 



The gas waste problem is concerned with the effects ui)on fishes of 

 the gas liquor untreated, the effect after the removal of the heavy tar, 

 the effect of tar, the effect of gas-washing water, and that of lime, etc. 

 from the purifiers. It is the purpose of this paper to show that essen- 

 tially all the products of the distillation of coal are very toxic to fishes, 

 some of the most toxic being those which are commonly regarded as 

 "insoluble" in water. From the standpoint of fishes the waste problem 

 is concerned with the reactions of fishes when encountering the pol- 



