FOREST, FISH AXD GAME COMMISSIONER. 151 



trout onlv two have a very marked anemia, while those with high readings 

 showed the most extensive ulceration. It is probable that the disease 

 reduces the hemoglobin only slightly if at all. 



Bacterial culture media, inoculated from the. blood of these trout, gave 

 no evidence of bacterial infection. Besides the ordinary media, fish agar of 

 alkaline, neutral and acid reaction was used, but the cultures in each case 

 usually remained sterile. Occasionally a secondary invader was obtained, 

 such as may not infrequently be found in trout weakened and dying from 

 other causes. 



To further determine the question of infection, direct inoculation 

 experiments were made. Two aquarium tanks were used, each of about ten 

 gallons capacity, supplied direct from its sources with cold spring water at 

 about 57 F. Into each tank were introduced nine wild brook trout from 

 four to eight inches in length, freshly caught from a natural pond above the 

 hatchery grounds, and which had not previously been in any water on the 

 station grounds. Each lot was fed with the regular station food, chopped 

 beef hearts, and, in addition, one lot received on several occasions small 

 portions of flesh containing the ulcers from the dying trout. 



By the thirteenth day marked symptoms and lesions had developed 

 among the trout which had. been inoculated by feeding the disease ulcers. 

 The largest of these, a male eight inches long, and which had been seen to 

 consume the ulcerated tissue in quantity was without visible lesions, but 

 respired at the rate of 120 per minute. The respiration of the largest con- 

 trol trout, a somewhat smaller fish, was eighty per minute. Of the others 

 of the inoculated lot, seven showed external lesions, one a moderate exoph- 

 thalmia of both eyes, two had sloughing areas upon snout, another an 

 inflamed anal fin with sloughing of first rays and a slight protrusion of one 

 eye, the others with slight bloody extravasations upon the sides. The trout 

 with the sloughing anal had a respiration of 140 per minute. 



On the fourteenth day, the largest trout of the inoculated individuals 

 died with slight bloody extravasations about mandible. Its heart blood 

 was sterile. On the sixteenth day, two others died, one with a typical 

 ulcer, like those of the trout dying in the ponds, but much smaller. On the 

 eighteenth day, another died, and on the twentieth day, two more, one of 

 which bore several of the characteristic ulcers. On the twenty-second day, 



