AMERICAN FISHERIES SOCIETY. 89 



ers decided to send Dr. Charles M. Blackford of Washington, 

 D. C, to study it. This <;enllenian, who is making a study of 

 diseases of lish, remained at Allentowu for nearly two weeks, 

 and his findings coincided with mine as far as the question of 

 inbreeding is concerned, but he did not appear to think the 

 catastrophe was hastened by unsuitable water conditions, but 

 Dr. Blackford was, and is probably yet, unaware of a fact 

 which only came to my knowledge a number of weeks later, 

 namely, that out of some thirty thousand fry of the winter's 

 hatching distributed in retaining ponds in a ditierent part of 

 the state, more than one third did not die, the holders of these 

 fry merely contenting themselves with complaining of an un- 

 usually bad lot of fish, of which the greater number died and 

 the remainder were very small. These persons were entirely 

 ignorant of the mortality at Allentowu. Thus it will be seen 

 that while all the fish remaining in the Allentowu troughs died, 

 a proportion of those given other environments escaped the 

 same fate. This to my mind is conclusive evidence that there 

 was some other immediate cause for the sudden loss of the fish 

 than low vitality, due to persistent inbreeding. 



Dr. Blackford's report is exceedingly interesting and was 

 made in duplicate to me for the Pennsylvania Fish Commis- 

 sion and to the United States Commission. 

 Dr. Blackford says in part: 



"During the winter of 1898-99 approximately two million 

 brook trout were hatched in the Allentowu station. The ova 

 are hatched on beds of gravel and wire gauze trays. * * * 

 The water is brought into the houses by an open trough that 

 extends the entire length of the buildings and is pierced by 

 cocks that allow a regulated amount of water to flow into the 

 shallow troughs in which the eggs are hatched. This arrange- 

 ment allows the water to become aerated and enables the dead 

 or fungoid eggs to be readily fished out. After hatching, the 

 fry are retained in the hatching troughs. These troughs are of 

 wood. * * * At the lower end of each trough a screen 

 of wire gauze extends across it from side to side, and between 

 this screen and the end of the trough is the outlet. * * * 

 The fish from w^hich milt and ova are taken are reared in the 

 hatchery and are the descendants of those brought to this sta- 

 tion when it was removed from Marietta. 



"In 1898 the fish began spawning very early, and spawn was 

 taken on October 8. The period of incubation was short, only 

 35 to 42 days, and the fry are small. 



"The troughs containing the fry were scrupulously clean, no 



algae or growths of any kind being found in them. The fry 



were huddled about the upper end, crowding so thickly around 



the inlet that they concealed the bottom, except the place on 



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