14 Fishery Board for Scotland. 



glistening white fibrous skin is thinned out over the big hulk of the 

 tumour, permitting the red colour of the latter to shine through. 

 The fibres run into the wall of the .swim-bladder. In forcing its 

 way into the abdominal cavity, the tumour had displaced some of 

 the ribs. 



The tumour had also pushed itself dorsally between the 

 lateral processes of the vertebrae. Among the muscles it was 

 enclosed in a tough fibrous envelope, to which it was loosely 

 attached. The lateral trunk muscles had been displaced (fig. 122). 

 One of the a. groups of muscles seemed to have disappeared, while 

 several of the b. groups were distorted. 



The lateral processes of the vertebra? have been deflected (fig. 

 120), and the ribs have been displaced from their attachment to 

 them. Flat bony plates have developed to connect the separated 

 bones, e.g., tv. It is difficult to decide whether the rib marked 

 (r 2 .) or the lateral process had been broken or not. In this case 

 there were four little bones joined together by ligature, connecting 

 the rib to the vertebra. In this figure, parts of the tumour are 

 indicated by (/*..). 



When cut open the tumour was found to be white inside. It is 

 of a fibrous, spongy structure. It could be readily torn. An 

 inside portion was of a pink colour. A section was cut by means 

 of the freezing microtome (fig. 114). It showed a mass of irregular 

 fibres, which showed a tendency here and there to run parallel to 

 one another. There were small cells, some oval, others spindle- 

 shaped. The tissue exhibited cavities, and also concentrated areas 

 that resemble the section of a muscle bundle. 



Cancerous Tissues in Fishes. 



Several morbid tissues from fishes were sent to Dr. F. M. Milne, 

 Clinical Pathologist, Royal Infirmary, Dundee. He very kindly 

 cut sections of these specimens, and also very courteously gave me 

 his opinion of their nature. 



Two of the tumours he diagnosed as cancerous. Sections of them 

 are shown in figs. 53 and 52. The former (fig. 53) was made from 

 a tumour which was reported to have been found in the abdominal 

 cavity of a catfish (Anarrhichas lupus). It appeared to be a 

 colloid carcinoma. The nests of epithelial cells are shown. 

 Vacuoles were observed in the nests, e.g., ra. They appeared to be 

 filled with some coagulated material. JV' and n" indicate the 

 position of two other nests. An inflamed condition is seen at one end 

 of the section, indicated by the closely-packed cells. 



The second tumour (fig. 52) was found in the urinary bladder of 

 a cod (Gadus callarias). The epithelium (ep.) is working its way 

 down in the form of nests (n.) through the wall of the bladder. On 

 the other side of the epithelium is a crystalline deposit (cr.), formed 

 in consequence of the inflamed condition of the bladder wall. The 

 epithelium cells are continued right into the crystalline deposit. This 

 mass (cr.) appears to consist of enlarged and distorted epithelium 

 tissue. It is a squamous Epithelioma. 



Lymphostasis in Fishes. 



Saithe (Gadus virens). — A very large tumour was found in the 

 dorsal part of the pectoral region. It measured 5 inches (12 cm.) 



