Thomas. — Effects of Certain Oils Upon Brook Trout 123 



As much as 500 parts of the above oil added to 1,000,000 parts 

 of water showed no effect upon the fish. The oil, however, emul- 

 sified with the water after the air had kept it in constant motion 

 for several days. After this emulsification took place the fish 

 refused to eat (about seven days). The fish would then die in a 

 few days, partly because of lack of sufficient food, and more 

 directly because the gill membranes became coated with the 

 emulsion. If the solutions were not areated the oil would not 

 emulsify and the fish lived well provided the water was changed 

 often enough to insure sufficient oxygen. 



"No. 5907 is a crude water-gas tar obtained from our local 

 gas company. It is produced by decomposition of petroleum 

 products for the enrichment of carbureted water-gas. This par- 

 ticular sample is free from water and consists of benzol, toluol, 

 a small amount of naphthalene, and numerous other high-boiling 

 hydrocarbons of the benzene series." 



In a mixture of 66 parts of tar to 1,000,000 of water the fish 

 began to dart immediately and showed irritation of the gill mem- 

 branes. The following experiments may be cited to show the 

 degree of toxicity of such a mixture: 



Experiment 5907-1. 



No. of fish: 1. 



Used: 0.1 cc. tar No. 5907; 1500 cc. water, (i. e.,QQ: 1,000,000). 



Put in solution 10:12 A. M., October 23, 1914. 



Fish began to dart at once showing irritation of gill mem- 

 branes. Put in water containing no tar at 10:20 A. M. Began to 

 revive by 10:30 A. M. Jumped out of jar but was replaced appar- 

 ently uninjured. Began to swim normally by 11:30 A. M. Put 

 back into tar solution at 5:00 P. M. Removed to water con- 

 taining no tar at 5:05 P. M. Was at this time in same condition 

 as at 10:20 A. M. By 5:20 P. M. no improvement was shown — 

 nearly dead. Observed at 10:00 P. M. and found dead. 



Experiment 5907-2. 



No. of fish: 1. 



Used: 0.02 cc. tar No. 5907; 1500 cc. water, (i. e., 13.3: 

 1,000,000). 



Put in solution 10:13 A. M., October 29, 1914. 



Showed signs of irritation at once. 11:15 A. M., body showed 

 faint pink coloration. Swimming on back 2:00 P. M. On back 

 at bottom 3:00 P. M. Transferred to water containing no tar. 



