Biological Survey — Erie-Niagara Watershed 145 



Effects of Weak Acid Solution upon Fish. — Since acids are 

 among the most common polluting substances found in streams 

 and also since they are frequently employed in trout hatcheries 

 to check the spread of certain infections, studies with very weak 

 acetic acid solutions were undertaken. The general method of 

 the experiment consisted in placing twenty-two liters of water in 

 each of two wooden buckets. Holes were bored in the close fitting 

 tops to allow the passage of glass tubes. Through these tubes air 

 was blown in a constant stream throughout the experiment. To 

 the water in one bucket was added 6 cubic centimeters of glacial 

 acetic acid. This renders the tap water in the bucket very faintly 

 acid. The acid can hardly be tasted. Since these were merely 

 initial experiments, the resulting hydrogen ion concentration was 

 not measured. Fish were placed in aerated solutions of acid and 

 tap water. After a definite period of time they w^ere removed 

 and hemoglobin determinations run upon the blood. Erythrocyte 

 counts were also made at the same time. After the first fcAV runs 

 when it was found that the fish in the bucket of aerated water 

 were unchanged and uninjured, only the acid experiments were 

 continued. In all cases fish left in the acid for even a brief 

 period, and in this very weak acid, showed a skin response in the 

 form of a dense white coating of mucus over the entire body 

 including the eyes. This leads one to wonder whether the much 

 stronger acids in which trout are bathed during hatchery infec- 

 tions produce their effects due to direct action upon the organisms 

 that are attacking the skin or due to the indirect action from the 

 formation of a mucus coating. 



Table 2 incorporates some of the preliminary data obtained in 

 the experiments upon acids. Table 3 has been presented to show 

 the number of red cells, erythrocytes, that are required in normal 

 fish to furnish a hundred per cent hemoglobin. This is obtained 

 by dividing the number of red cells formed by the hemoglobin per 

 cent after the per cent is changed to a decimal. 



Although the data of these tables are much too meagre to 

 premit of any fair statistical treatment they suggest that the acid 

 causes the number of red cells to diminish without changing the 

 hemoglobin. Such an effect is shown when the number of red cells 

 to contain one hundred per cent hemoglobin is calculated. Since 

 there are some obvious exceptions in these data, nothing more 

 than suggestions can be presented. These, however, afford definite 

 opportunities for much more extensive experimental work. 



