106 REPORT OF COMMISSIONERS OF INLAND FISHERIES. 



the access of oxygen, and to avoid contact with injurious metalhc 

 substances. 



To cany into effect this principle we propose the following method : 

 To use for transportation an iron tank enameled on the inside with a 

 vitreous substance in order to prevent contact of the water with the 

 metal ; to use only water dipped from the water in which the animals 

 have been living, in order to insure its proper constitution; to sur- 

 round the tank with a jacket into which ice or warm water can be put 

 to control the temperature ' (for many animals, at any rate, both 

 among fishes and invertebrates we have found by experience that a 

 low temperature is a very important factor in maintaining life when 

 the animals are crowded into a small amount of unrenewed water) ; 

 to provide both the current and the continuous respiration by in- 

 stalling a propeller device of enameled iron kept in motion by means 

 of a spring motor. 



