FISHERIES, GAME AND FORESTS. 1 77 



actions of the fish were indicative of their diseased condition, for they would 

 frequently rise to the surface and swim upon the side or turn belly-up on the surface, 

 while at one period hundreds of the dead fish were daily removed from the runways. 

 In some of these there were no external indications of the disease; in others, and in 

 the majority of the cases, great red spots or ulcers were visible, sometimes on the 

 belly, again on the back, but most often on the sides. The bases of the fins were 

 particularly subject to these sores and the eyes were often disfigured by them. More 

 serious disfigurements were frequently seen in the entire loss of one half of the lower 

 jaw, bone and tissues being eaten entirely away (Plate I) ; or, again, the ulcers in the 

 sides would give rise to holes through the body wall and into the body cavity, and 

 live fish were occasionally seen with parts of their viscera hanging out of the holes 

 thus made (Plate II). The red ulcers which are due to the congestion of the blood at 

 the sore spots give place to wide gaping wounds sometimes an inch in diameter where 

 the flesh has dropped out (Plate II). In some cases the vertebrae in the caudal 

 region were thus exposed. In many cases the holes or sores did not go entirely 

 through the body wall but formed shallow and irregular wounds. These sores were 

 most apparent on the small yearlings ; the older fish, however, were not exempt but 

 in these cases the sores were proportionately smaller and distributed in all regions of 

 the body. 



Aetfyods Employed in tl)e Investigation. 



The wide distribution of the sores about the animal, from the posterior end of the 

 body to the eyes and jaws, was sufficient evidence that the cause of the disease was 

 pretty well distributed throughout the organism, and if further evidence was 

 necessary, it was furnished by the cases mentioned above where the fish were found 

 dead with no external sores of any kind. It was at once apparent from these facts 

 that the cause of the trouble was of some deep-lying nature and that, if parasites 

 were at the bottom of it, they must be widely distributed among the various organs 

 in the body and probably carried to all parts by the blood and lymph circulation. 

 The various organs of diseased fish were therefore cut into small pieces and preserved 

 in diverse killing agents, including sublimate acetic, (saturated corrosive sublimate 

 with five per cent, glacial acetic), saturated corrosive sublimate in normal salt solution, 

 and Flemming's fluid (osmic acid, chromic acid, and glacial acetic acid in certain 

 definite proportions) The organs thus preserved included the testis, kidney, ovary, 

 gall bladder, pyloric cceca, digestive tract (including stomach and intestine), liver, 

 gills, and sore spots in the outer wall. These were taken to the laboratory, where 

 they were sectioned in paraffine and stained in various ways, the most satisfactory 



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