58 



only held in suspension in a certain proportion in accord- 

 ance with temperature, it is evident that they are not likely 

 to collect in amount sufficient to be injurious, except in 

 the absence of a normal proportion of oxygen. It is prob- 

 able also that the gases resulting from decomposition are 

 very largely oxydized in water, and the only element of 

 danger with which we have to deal to any extent is car- 

 bonic acid gas. 



In the atmosj^here, on the contrary, it is thought by Djc. 

 Angus Smith that the injurious effects resulting from the 

 presence of noxious gases are due to those generating from 

 decomposition, rather than from carbonic acid gas. 



Suggestions tending to the elimination of the carbonic 

 acid gas from water used in fish transportation by the use 

 of lime-water, or other chemicals, have been advanced, but 

 these are in the same line, inducing complexity of method 

 and requiring almost scientific accuracy and judgment on 

 the part of the persons emjDloyed. 



It seems to me a rational conclusion that any form of 

 close confinement or of chemical elimination of noxious 

 gases in the shipment of fishes is not only complex and 

 useless, but may be either positively injurious or danger- 

 ous, and that whatever imj^rovements are made in our 

 systems will be in the direction of more efficient and auto- 

 matic aeration. 



According to Parkes, "As it falls through the air, rain 

 becomes more highly aerated (average twenty-five cubic 

 centimeters per liter), the oxygen being in larger propor- 

 tion than in atmospheric air (thirty-two per cent, or a little 

 more); carbon dioxide constitutes two and one-half or 

 three per cent, of the gas." The same results in aeration 

 are attained by an efficient method of passing air through 

 the water. 



The use of much ice in carrying fishes must undoubtedly 

 induce inflammation of the gills and mucus membrane to a 

 greater or less extent. Ice-water is heavy and non-aerated, 



