STIMULATION BY THE MINERAL ACIDS, HYDROCHLORIC, SULFURIC, AND NITRIC, IN THE SUNFISH EUPOMOTIS

Abstract

The stimulating efficiency of these acids was measured by a method which reduces experimental errors to a minimum. Features of the method are the constant rate of flow of solution and spring water over the fish, allowance of ample time for recovery, and measurement of the (H+) of each solution by the quinhydrone electrode. 18 fish were used for 6 months resulting in 628 observations. Stimulation by these acids is primarily dependent upon the (H+) and the reaction time is expressed by the equation (RT-5) = -4.3 log(H+ X 104) +9.118. Any effect of the chloride, sulfate and nitrate ions must itself be measured by the (H+). Freshly collected animals show a lower threshold for stimulation than do laboratory-adapted animals, but relatively the two groups behave similarly.