112 EEPORT OF THE COMMISSIONER OF FISHERIES. 



exposed to the air by its flow as a creek of many falls and cascades, 

 and this corrects it completely. 



Water supply at White /Sulphur Springs station. — A visit was made 

 to White Sulphur Springs station in January and February to investi- 

 gate the mortality among trout fry there. It was shown that the sta- 

 tion water varied from time to time in its supply of dissolved oxygen, 

 and was for a part of the time markedly deficient in oxygen. There 

 was possibly at the same time a deficiency in the nitrogen dissolved, 

 but the necessary apparatus to determine this was not available at that 

 time. An aerating and de-aerating apparatus on a small scale was put 

 in practice by lowering one trough to the floor and passing its supply 

 through a perforated box, the water falling a few feet in slender 

 streams. This arrangement caused a marked reduction in the losses, 

 but did not entirely prevent them. The presumption is that a more 

 complete process of the same sort would correct the water entirely. 



Mortality at Allentown^ Pa. — In October and November study was 

 made of a mortality among brook-trout fry at the Allentown hatchery 

 of the Pennsylvania Board of Fish Commissioners. The disease 

 proved to be an anasmia which was finally ascribed to long continued 

 housing of the fry in large numbers in hatchery troughs. The prog- 

 ress of the disease in the afl'ected brood could not be arrested, but 

 terminated naturally, leaving a considerable percentage of fry in 

 apparently good condition. 



Contaynination of oysters at Great South Bay^ Long Island. — Repre- 

 sentations having reached the Department of State through certain 

 ofiicials in London that oysters received from New York were con- 

 taminated with sewage and presumably with typhoid germs, the matter 

 was taken up by the Bureau, and in February an examination was made 

 of certain oyster beds at Great South Bay, from which the contam- 

 inated oysters were alleged to have come. 



Oysters freshly taken from the beds named, and similar oysters held 

 for two or three days in floats on the bay shore were examined bacterio- 

 logically and were wholly free from sewage contamination. At 

 Patchogue, oyster beds were found exposed to sewage, and though 

 oysters taken from them were also free from sewage at this time, 

 some danger must have existed, especially at other seasons. The prac- 

 tice of floating oysters close to shore, even when not at the mouths of 

 creeks or rivers, was found to be more or less a menace to the health 

 of oyster consumers. 



The oysters alleged to have been impure were taken in November 

 and December, while the investigation was made in February follow- 

 ing. Though the beds were then found free of contamination, the 

 method of floating the oysters near shore might easily result in their 

 contamination during the warmer months of the season, and it is 



