402 



Thiophene. 



It occurs as an impurity in commercial benzene. It is not par- 

 ticularly poisonous to man. In a one hour fatal concentration fishes 

 are intoxicated showing signs of stimulation and some staggering 

 after about 20 minutes. These symptoms were followed by intoxica- 

 tion. Sunfishes, basses and minnows were all positive to fatal con- 

 centrations (Chart III, graphs 33 and 34). 



Acetone. 



It occurs in connection with benzene (Lunge 3d ed, pp. 176). 

 For the fish experiments it was added to the water and the final ex- 

 periments performed in a four-liter bottle. It is only slightly poison- 

 ous to man and least toxic to fishes of the compounds studied. Fishes 

 of various sorts are positive to it, particularly to the weaker concen- 

 trations (Chart IV, graph 35). 



Benzoic acid. 



It occurs as a residual in the manufacture of phenol, and in coal 

 tar "oils". It is less toxic than most other coal tar products. It ap- 

 pears to be only slightly poisonous to man. The dry powder was 

 weighed and dissolved in water. Fishes of various sorts are negative 

 to it (Chart IV, graph 36). 



Phenols and the Cresols. 



According to Witthaus and Becker, 5% solution of any of these 

 coagulates protein, narcotizes partially and finally paralyzes the ner- 

 vous system. It occurs in coal-tar and in gas-liquor and is one of the 

 sources of the toxicity of wastes. For the work on fishes the solid 

 crystals were melted, one cc. was accurately measured, and added to 

 a liter of water, and dilutions made from this solution, which was 

 kept tightly corked. 



Phenol is a powerful irritant, producing stupor and shallow ir- 

 regular breathing in man when taken in small quantities. Larger 

 quantities are rapidly fatal. Strong concentrations such as i cc. per 

 liter are very rapidly fatal to fishes, but solutions of ^ to % this 

 amount kill standard fishes only after one hour or more. In such 

 solutions the fishes make a few erratic movements, turn on their sides 

 and remain for a long period with faint respiratory movements and 

 slight swimming movements of the fins. Fishes dying in it are char- 

 acterized by a gaping condition of the gills which is common if 



