THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 231 
this account the fishermen often estimate the weight at nearly double 
the actual (Railliet.) 
According to Vet. Surg. Hanzo, the affected fishes float on the surface 
as though poisoned with Cocculus indicus. 
EHpidemics.—In the Meuse it has manifested itself with the characters 
of a veritable epidemic during three consecutive years, from 1883 to 
1885, inclusive. It became progressively more aggravated, reaching 
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 only 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 Méziéres 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 Monthermé and Givet. 
In the neighborhood of Nancy the barbels die in great numbers 
(Mégnin). 
In the Aisne Railliet was informed of ravages of the disease occur- 
ring near Rethel. The disease, he thinks, extended to the Aisne and 
the Marne from the 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 of July, at which 
date Railliet’s information ceased. 
In the Seine it did not extend above the Port a VAnglais 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 Marne. 
In the Rhine and its tributaries, the Saar and Mosel, according to 
Ludwig, it seems tu 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 Pfeiffer, 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 6 or 7 
kilograms. 
