The relation of fishes to ions in their natural environments . were run. Of the 18 graphs, 14 show that the fishes spent 90^ of the time in the acid half of the tank; 3 show more than 50$ of the time in this half and 1 (small blue- gill) shows an R0^ preference for the neutral vnd. That the fishes are negative to neutral water is thus confirmed. To ascertain the cherai- at the point cal reaction of the waterAin the tank where the fishes turned back fromthe neutral end, numerous samples were titrated from this region,duringthe experiment. They showed that the water at this point contained 1
The relation of fishes to ions in their natural environments . were run. Of the 18 graphs, 14 show that the fishes spent 90^ of the time in the acid half of the tank; 3 show more than 50$ of the time in this half and 1 (small blue- gill) shows an R0^ preference for the neutral vnd. That the fishes are negative to neutral water is thus confirmed. To ascertain the cherai- at the point cal reaction of the waterAin the tank where the fishes turned back fromthe neutral end, numerous samples were titrated from this region,duringthe experiment. They showed that the water at this point contained 1 C02 per liter. The graphs shown in Chart T are typical for all, IMioua c. Reaction, to Acidity in Mstilled Water. The distilled water available in quantity from the chemistrydepartment, was not rapidly toxic to the fishes and since the foregoingresults are of some general biological importance, it was decided torepeat the experiments in distilled water. This -iLH^l water wasfaintly acid with COgcontaining S-3 per liter. It contained no . (~. salts;30 the addition of a strong acid resulted in ro complicationssuch as those discussed in the case of the tap water. A imager of ex-periments was performed with various strengths of acid and alkali. Theneutral portion of the bank was kept track of by meano of titrations,and the reactions of the fishes to this neutral region especially results are presented in table 2| in brief they are as follows. Thefishes spent practically all the time in the acid -portion of the tank,turning back from the alkaline end at a point just on the acid side ofneutrality. They did not however, select the highest acidity available,but swam back and forth in the tank, between neutrality on the ©jad handand about •0008M K?SO^ on the other. (The small amount of COp presentin tba iistilled v/ater may be neglected in the presence of the muchmor* ionized acid). At the range of dilution, used in these experiments,carbonic acid would ho
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfishes, bookyear1915
