2l8 TWELFTH ANNUAL REPORT OF THE 



lake trout, maskalonge and other species, the red plague of the eel, and 

 many similar serious affections would be unknown and millions of fishes 

 would be added to the supply for distribution. 



If to these causes of mortality be added the many organic diseases 

 arising from a multitude of causes, and the disorders due to parasitic crus- 

 taceans, the wonder grows that the results of artificial breeding are not on 

 the decline, but steadily increasing year after year. Some idea of the 

 difficulties to be overcome may be gained from a glance at the admirable 

 Handbook of Fish Diseases by Prof. Hofer, of Munich, a condensed account 

 of the subject, but comprising 359 octavo pages, and showing a bewildering 

 array of disorders among fishes, particularly those known in fish culture and 

 the fisheries. 



Translations of several of Dr. Hofer's articles were made and copies of 

 them were sent to Foremen Walters and Davidson for their information. 

 It is intended to translate all of the papers relating to the fishes of New 

 York for the benefit primarily of our own foremen. 



Furunculosis or Ulcer Disease. 



The disease infects the brown trout and the American brook trout 

 which have been cultivated in European hatcheries for some years, and it 

 affects yearling fish as well as adults. Carp and other fish are not so suscept- 

 ible to it; even among the Salmonidae, the rainbow trout up to this time 

 has been immune from it. 



The disease is most prevalent at spawning time — in the autumn 

 months — although in many places it occurs the year around. The 

 symptoms of the ulcer disease, according to the author's observations, are 

 the following : 



The first signs are most apparent in an extensive inflammation of the 

 intestine and sometimes in the peritoneum. The entire middle and lower 

 intestine will then appear very red and bloody — often so much so that 

 death will ensue, although many of the fish survive the first stage. Some- 

 times the symptoms of enteritis are lacking, and the second stage manifests 

 itself directly. In the scattered muscles, both in the deeper parts as well 

 as in the superficial, hemorrhagic spots appear which are plainly distin- 



