2 26 TWELFTH ANNUAL REPORT OF THE 



of eels were destroyed by it in the ponds of Commachio. In 1825 the well 

 known embryologist Coste writes about a great mortality among the eels. 

 Still later, from 1850 to 1864 and again in 1867 similar reports came from 

 Italian wfiters. 



In 1892 Canestrini observed the Red Plague in the eel again in Com- 

 machio, and especially in Campo Mazzano. Sennebogen recognized the 

 same disease in Venetian waters and on the Dalmatian coast in 1884, 1885 

 and 1889; also in Herzegovina in 1898-99. 



The epidemic was very marked in Danish waters from Seeland to 

 Ruegen in 1896, and reappeared in the same region in 1897. 



Sometimes in Seeland waters many thousands of eels die especially 

 when they are overcrowded in ponds. The latest information about this 

 disease is from Inghilleri, based on the observations of Prof. Gosio, to the 

 effect that the same thing appeared in 1901 in ponds at Orbetello, in the 

 vicinity of Grossetto, on the coast of the Tyrrhenian Sea. 



The essential external symptoms of the disease, according to the 

 author's investigations, consist in an intense redness or elongate circum- 

 scribed ecchymoses of the side of the abdomen, also in an especially well 

 defined ring-shaped redness around the vent, in an equally distinct redness 

 of the fins, and in scattered patches of inflammation of the skin on the back 

 and sides of the body. Of the internal organs the intestinal tract appears 

 seriously affected, especially the dorsal stomach wall. 



According to the observations of Sennebogen, who has often studied 

 the Red Plague in living eels, the fins first become intensely reddened on the 

 surface, then isolated body spots appear, particularly in the region of 

 the liver — ■ at first small, point like, cherry red, hemorrhagic spots which 

 gradually enlarge and expand into large red spots. The dead eels soon 

 putrefy and pollute the air. Sennebogen observes that even before the 

 eels are quite dead the tail may be decomposed. 



The progress of the Red Plague is extremely rapid. According to 

 Sennebogen the disease develops very quickly, the afflicted animals come to 

 the surface, attempt to leave the ponds, become very feeble, even in the 

 course of two hours the tail especially becomes completely inflexible and 

 paralyzed, and shortly afterward death intervenes. The disease attacks 

 particularly the large female eels when they are about to spawn. It is 



