SEA-FISHERIES LABORATORY. 81 



unfit for human food. The flesh was " knobby" and 

 " full of tumours." There was general discoloration 

 along the ventral surfaces near the fin ; and a large, 

 black, soft area there showed that there was extensive 

 destruction of muscular tissue. On cutting into this 

 softer part of the fish it was seen that there was consider- 

 able necrosis, for a dense black, pultaceous fluid oozed 

 out, leaving a large cavity. On cutting through the fish 

 in various planes it was seen that there were very 

 numerous tumours in the muscles of the abdominal 

 region on either side of the ovaries, and above and below 

 the latter in the muscles surrounding the vertical fin 

 skeleton. The tail of the fish was also very greatly eroded 

 and swollen, and there were very many small tumours in 

 the tissues beneath the integument in this region. 



Malignant Tumours in Marine Fishes. 



A fairly large number of cases of the occurrence of 

 malignant growths in fishes have now been described, 

 and one may say something as to the general character 

 of these abnormalities. Benign tumours are not very 

 uncommon in marine fishes. Usually these growths are 

 such as would be called "wens" in man. They occur 

 just beneath the integument, on nearly all parts of the 

 body, and they are sometimes found in the body cavity, 

 as growths of the peritoneal tissues. They are fibrous in 

 nature, "hard" or "soft," and they are always very 

 distinctly capsulated so that they can easily be "shelled- 

 out." Examination of a large number of sea fishes 

 exposed in public markets may reveal one or two cases of 

 growths of this nature. 



Malignant tumours are more rare, but even these may 

 be found by examining fairly large numbers of fish. 

 Those that I have seen myself have occurred in Skates, 



