FOREST, FISH AND GAME COMMISSIONER. 22 1 



trout. The disease bears the name " Spot Disease " because it appears on 

 the skin of the brook trout in the form of irregular spots of different sizes 

 which persist in one place until the epidermis is loosened and the true skin 



exposed to view. The spots are outwardly flat and have a dull gray 

 appearance. Secondary fungus growths are very noticeable on these spots. 

 A; the same time the diseased brook trout shows a very intense inflammation 

 of the great intestine so that on the slightest touch against the side of the 

 bellv the fish exudes a bloody, mattery mass from the intestine. This 

 sometimes flows from the fish just as readily if it is lifted up by the head. 

 The disease progresses very rapidly; the sick fish swim excitedly here and 

 there, try to jump out of the water, and die after a few days. 



Up to this time researches as to the cause of the spot disease have not 

 furnished a conclusion. This much indeed is established, that in the spot 

 disease we have to deal with a bacterial infection; meanwhile the specific 

 causative bacillus has not yet been made known in clear cultures. For this 

 reason it is impossible to establish the relation between the spot disease and 

 the condition through which the disease giving bacillus originates and 

 increases so that we can positively identify the bacillus like that of furuncu- 

 losis. It is not impossible that in the case of the spot disease putrefactive 

 processes in pond water furnish the basis for a most probable origin of 

 the bacillus, perhaps in consequence of pollution through remains of food. 

 Meanwhile, when the disease originating bacillus is found, we will acquire 

 positive knowledge. 



The Red Plague of the Carp Like Fishes. 



(Hofcr, Handbuch der Fischkrankheiten, pp. 12-15.) 



There is a certain disease which attacks carp, tench and perhaps other 

 fish of the carp family which is particularly bad in fish ponds and which is 

 therefore often called "Pond Disease." This name is wrong only in so 

 far that numerous other diseases also originate in ponds. The disease is 

 not infrequently observed even in winter ponds. It is by no means limited 

 and localized to one spot, but has already become established in widely 

 separated parts of Germany, so that after close investigation of its distri- 

 bution, it is regarded as one of the commonest diseases. 



