12 American Fisheries Society 



free water. It gives an unanswerable argument, incontrovertible 

 evidence in establishing the pollution of the stream; you have 

 evidence not only that the existence of fish has been interfered 

 with, but that if the fish were restored to the stream they would 

 not find at the present time proper conditions for their existence 

 there. 



Now at various points in the country we are raising very 

 considerable quantities of young fish. Those fish represent 

 money. Each can of fry or fingerlings is a definite sum that the 

 people of the state or the nation have put into this means for 

 the replenishment of the water. And of what value is it, gentle- 

 men, to pour fish into the stream where an examination of the 

 conditions reveals the impossibility for the continued existence 

 of such organisms. 



I have hardly any need to remind you that it is the young 

 fish which are of all most sensitive. All people have experimentally 

 tried at times to make use of that sensitiveness as a measure 

 of pollution. They have taken small or young fish and used 

 them as tests of the purity of the stream. I want to try to show 

 you the rather superficial character. — if you will permit me, 

 with apologies, to designate it in that way, — of such a test by 

 translating it into human terms, for this question is exactly the 

 same problem that has concerned medical men and sanitary 

 experts in seeking to control the condition of the air in manu- 

 facturing plants. Suppose a manufacturing plant were cited by 

 a sanitary official for polluting the atmosphere and endangering 

 the health of the workmen, and the expert should take a dozen 

 children and divide them into two groups; six of them permitted 

 to play in the air outside; and six were set on the floor of the 

 manufacturing establishment for three hours or five hours. If 

 they died the conditions were to be declared such as to demon- 

 strate pollution of the atmosphere, and I do not suppose anyone 

 would doubt that; but, gentlemen, the conditions with which 

 we really have to deal are never so extreme as that. I would 

 challenge you to cite a case of atmospheric pollution that would 

 kill off even sensitive children within three or four hours. And 

 yet that is what the same people expect the minnow test to do, 

 to decide between what is right and not right. Of course if the 

 minnows are killed, conditions are bad enough to demand instan- 



