440 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



A small quantity of sewage (that is from a few private sewers) is dis- 

 charged iuto Fourth Lake ; alsoeome chemicals from the laboratories of 

 the State university, and also a little gas tar from the insane asylum 

 gas works situated on the north side of the lake opposite the city. The 

 sewage, waste chemicals, and tar are put into the lake at three points 

 each remote from the other. Bat it is also true that a much larger 

 amount of sewage is discharged iuto Third Lake, in volume not less 

 than three or four times that which is discharged iuto Fourth Lake and 

 as well as some gas tar. 



Dr. Hoy was called here, and has made an examination of the fish. 

 His report upon the same is to be sent to us later. He is also to write 

 you upon the subject. Professor Birge, of the State university, is saitl 

 to have made some examinations also, and is reported to have sent the 

 results of his examination to you. 



By express we send you ajar containing several of the fish taken just 

 before death. We hope that your examination of these fish, with the aid 

 of such suggestions as Dr. Hoy and Professor Birge may make, will 

 put you in possession of the facts of the case sufficiently for an opinion 

 as to the cause, and if possible enable you to suggest a remedy for this 

 calamity. It were a calamity if it wore merely the loss of the fish, but 

 there may be in it also a threat of sickness to our people. In passing 

 upon this matter will you be good enough to give your opinion upon 

 the significance of this as threatening sickness. 



It may be proper to state that various suggestions have been made 

 as to the cjuise of this trouble. One is that a small worm attacks the 

 gills or throat of the fish ; a worm is said to have been taken from a 

 "weed upon which the fish had been feeding, the weed being found to 

 some extent in the intestines of the fish. Anotlier is, that it is caused 

 by a parasite feeding upon the gills. Dr. Hoy undertook to analyze the 

 "water of the lake, and reports it nearly as pure as the artesian water 

 with which the city is supplied. 



It is also said that in years past the fish of this lake in considerable 

 numbers have died. Every year there are some dead fish. In or about 

 1844 the whitefish came ashore in quantities as great as the perch now, 

 and on several occasions fish in considerable numbers have come 

 ashore. (Philo Dunning, State Commissioner, and B. J. Stevens, Mayor 

 of Madison.) 



Madison, Wis., August 4, 1884. 



The Dead Perch in Wisconsin. — A singular disease is afi'ecting 

 the perch in the lake here, which I am unable as yet to account for. 

 They are dying in great numbers. About 200,000 have died in the past 

 two weeks. They show no trace of fungus or other disease. The only 

 thing which is unusual about them is the gills, which, with the liver, 

 are gorged with blood. Whether that is abnormal for a fish which dies 

 of disease, 1 do not know. There is no fungus, the dying fish having 

 a perfectly clear skin ; they are fat or lean, male or female, full or fasting. 



