water temperature of each vat and table was individually controlled each fish assay table controlled the temperature of a battery of twenty identical vessels in which static assays were conducted some bioassays were made in constant temperature controlled rooms the fishes were conditioned and tested at the average celsius temperature indicated in the tables of the examples these temperatures were accurate to within one degree the conditioning period varied between one to ten days the test fishes were transferred to 19 6 liter assay aquaria and starved for 24 hours before a chemical was added each aquarium contained 15 liters of water which was aerated by means of a single stone air breaker five fish per vessel was the common number tested the load grams of fish per liter of water varied as indicated in the examples control fish were conditioned in the same manner as the test fish but no chemical was added to the control vessels during the assays the control data are the first concentration 0 0 reported in the tables delineation bioassays determined primarily the lc 50 and lc 100 of stickleback and the lc 0 and lc 50 of salmonids the selectivity index lc 50 lc 50 compares the lethal concentrations that cause 50 mortalities for each species the safety index lc 0 lc 100 compares the maximum concentration that kills zero percent of a preferred species with the minimum concentration that kills 100 of a target.