American Fisheries Society. 303 



Mr. Clark : Oh, yes. 



Mr. Ravenel: The mere pouring in of the water could not 

 have been injurious? 



Mr. Clark : Xo ; l^ecause by the time I kept changing this 

 water I had got pretty near all Lake Michigan water. You could 

 see the air right in the water. Perhaps it is not so thoroughly 

 charged with the air, l)ut you could see the air in the water; but 

 solved the problem to my satisfaction, and the explanation is that 

 there was too much air in that water for those fish, and had J. 

 continued giving it to them I Avould have killed the fish. I could 

 not understand the reason of the trouble at that time, only that 

 we had too much of that kind of air, and now I see the problem 

 that he brings up here is that you take the air out by deaeration, 

 and I took the air out at that time by the stirring process. 



Prof. F. P. Gorhani : I am interested in the statement made 

 by Mr. ]Marsh, l)ecause it is along the line upon which I worked 

 some time ago. We must distingiiish between two sorts of gas 

 disease, the sort that Mr. Marsh describes, which undoubtedly is 

 due to the superabundance of air in the water, and another gas 

 disease which shows itself by the formation of gas bubljles in the 

 tissues of the fish. These bubbles are behind the eyes, causing 

 the "^popeye," or under the epidermis of the fishes, causing the 

 bubbles of gas which form on the fins. I think the second sort 

 cannot be explained by the presence of too much air in the wa- 

 ter. I do not see how you can get the air from the water, first 

 into the blood and then out into the tissues of the fish to form 

 the bubbles, without first killing the fish. The amount of nii- ])res- 

 ent in the blood vessels would soon kill the fish. A small l)iil)l)lo 

 of air in the vessels will kill the animal ahnost inimediately. 

 The fishes Avhich show the presence of "popeye" and large ])ub- 

 bles in the tissues, contain altogether too much air to have it pro- 

 duced in the blood vessels ; it would have killed the fish at the 

 verv first. It seems to me that the explanation wliicli I gave 

 some five or six years ago accounted for the presence of the largo 

 amount of gas behind the eyes and in the tissues quite satisfac- 

 torily. The change in tlK' pressure upon the gas in tlie air l)bid- 

 der of the fish, brought aliout In- placing the fish in an a(|uarinm 

 allows the gas in the air bladder to expand, and it works itselt" 

 out of the Idadder through the tissues back of the .■yes and into 



