CONTENTS. 



Page 

 Introduction 



The dejith or survival of various species after changes in the salinity of the water :>' 



The fatal effect of fresh water upon various salt-water fishes ; 



Effect of distilled water i , 



Symptoms preceding the death of salt-water fishes in fresh water i i 



Effect of surface abrasions i ,j 



Acclimatization ', i , i 



Endurance in water of low salinity ti;', 



Effect of transfer of brackish and fresh water fishes to salt water 06 



Changes in water density at the New York Aquarium 08 



Effect of alternation of fresh and salt water 68 



Age in relation to endurance of change of medium 1)9 



Adaptation to changes in the medium in nature 69 



Changes of weight resulting from changes in water density 70 



Changes of weight in living fishes 70 



Changes of weight in dead fishes ,. 82 



Permeability of the membranes to salts in solution 84 



Determinations of the chlorine passed into the water by the fishes 84 



Determinations of the chlorine in the tissues of fishes 89 



The part played by the gills In osmotic exchanges 97 



Historical review 101 



Summary and conclusions 104 



Supplementary note lOU 



Bibliography 1U7 



54 



