The Effect of Balanced Versus Unbalanced Solutions, of pH and Distilled Water on Fish

Abstract

The influence of salt solutions on various forms of aquatic life has been a fertile field of experiment for many years. The role of ions in the life of the cell is of fundamental importance: They are the controlling factors in all of its activities, in reproduction, metabolism, growth and finally in death. The questions which these experiments have sought to answer are many and various. What ions are essential in the life of the cell? What are their antagonisms one for another, and how are these antagonisms exerted? What part do these ions play in osmosis and how do they do it? Why is distilled water fatal to so many, if not all organisms, and what is the reason for this fatal effect? WYhy can some organisms withstand so wide a range in salinity, while others cannot? Why are some homoiwhile others are isosmotic to their environment? How is ionic action influenced by other, purely physical factors such as temperature and light? What is the evolutionary history of the of vertebrates and invertebrates, terrestrial and aquatic, marine and fresh water, and how has this blood functioned in the adaptation of organisms to new environments? These are some of the questions involved in this field of research to none of which a final answer has yet been given. Since the investigations of Ringer, Loeb and their co-workers it has been generally recognized that solutions lacking Na, K or Ca are more or less toxic to animals. It is believed that solutions containing these ions in approximately the proportions in which they occur in sea water are those best adapted to them. That this proportion is not fixed for all animals however is evidenced by the abundant occurrence of the latter in inland waters whose content of these and other ions vary within wide limits. In some isolated cases indeed it is claimed that animals can live in the absence of one or other of these elements. Thus Worley ('29) states that the rotifer, Brachionvlus mufillerin, lived well in synthetic sea water lacking Ca. Sumner ('07) states that Fundulus heteroclitus lived for three or four weeks or longer in 0.3 to 1.5 per cent solutions of NaCl in distilled water, and Bullot ('04) obtained similar results with Gamutiarus. Hess ('30, p. 45) says that Planlaria dorotocephala can live over a month and perhaps indefinitely in pure calcium * Contributions from the Scripps Institution of Oceanography, New Series, No. 10.