The myxosporidia, or psorosperms of fishes. 23 i 



tliis account the fisliermeu often estimate tlie weight at nearly double 

 the actual (Railliet.) 



According to Vet. Surg. Ilanzo, the alfected fishes float on the surface 

 as though i)oisonpd with Cocculns indicus. 



Epidemics. — In the Meuse it has manifested itself with the characters 

 of a veritable epidemic during three consecutive years, from 18S3 to 

 1885, inclusive. It became progressively more aggravated, reaidiing 

 its maximum of intensity towards the middle of 1885. On certain days 

 of that year M. Ladague had interred nearly 100 kilograms of barbels; 

 the Meuse was covered with dead fish. The disease subsided little by 

 little, and actually appeared to become extinct, but it could almost be 

 said that the combat closed for want of combatants. 



In the district of Ardennes it was remarked oidy in the Meuse itself; 

 all the affluents have always been spared. The maximum intensity, 

 according to Railliet, was reached about the middle of 1884. On certain 

 days, at Mezieres alone, as many as 100 kilos (about 200 pounds) were 

 interred. Some years later the disease had disappeared from that 

 region, but raged down stream at Montherme and Givet. 



In the neighborhood of Xancy the barbels die in great numbers 

 (Megnin). 



In the Aisne llailliet was informed of ravages of the disease occur- 

 ring near Rethel. The disease, he thinks, extended to the Aisne and 

 the Marne from tlie Moselle via the canals. 



In the Marne a considerable number of barbels floated dead or unable 

 to escape, down the lower Marne. The disease appears to have begun 

 (at least in the neighborhood of Charenton) about June 15: thence it 

 progressively increased, attaining its maximum at the time of emptying 

 of the St. Maurice Canal. It persisted till the end ol" July, at which 

 date Railliet's information ceased. 



In the Seine it did not extend above the Port a 1' Anglais dam. The 

 Grenelle fishermen, Railliet was informed, had seen a great number of 

 sick barbels. The Seine thus appears invaded, without doubt consecu- 

 tively, from the JNIarne. 



In the Rhine and its tributaries, the Saar and Mosel, according to 

 Lndwig, it seems to have appeared at least several decades ago without, 

 however, ever having attained the magnitude that it has reached in 

 late years in the Mosel. The disease has there been observed since the 

 end of 1870 and has so increased that, especially in the warm summer 

 months, the dying and dead fish from the upper Mosel and Saar pass 

 Trier by the hundreds, and at Zell (on the Mosel) it is reported that they 

 spread a carrion like odor. According to Pfeififer, in the Saar and Mosel 

 during the summer of 1890 no very extensive mortality occurred. 



Contributory causes. — As regards age as a predisposing factor, Railliet 

 observes that in the Meuse the young barbels are attacked as well as 

 the old, the weights of dead fish varying from 22 grams to G or 7 

 kilograms. 



