284 G. H. DREW. 



A FIBRO-SAKCOMA OF A PLAICE (PLEUEONECTES 



PLATESSA). 



This tumour was found on a plaice caught at Plymouth, and was 

 brought up to the Laboratory a few hours after death. The fish was a 

 female, 12 inches long, and was in good condition. 



The growth consisted of a white ovoid mass situated over the oper- 

 culum on the ocular surface of the fish. It measured about f inch by 

 i inch along its longest and shortest axes respectively. It was soft to 

 the touch and was covered with a very delicate epithelial layer con- 

 taining a few pigment cells. Sections showed that the tumour was a 

 fibro-sarcoma, similar to the fibromata and fibro-sarcomata that are 

 relatively of such common occurrence on the opercula of plaice, but in 

 this case the sarcomatous element prevailed to a much greater extent 

 than usual. No metastases were present. 



A TUMOUR OF A WHITING (GADUS MEELANGUS). 



This tumour occurred in a male whiting, measuring 20 inches in 

 length, caught at Plymouth. Its position and relative size are shown 

 in Fig 4. It was soft in consistency, greyish in colour, but flecked 

 with red from the presence of blood-vessels. The surface was bare 

 and uncovered by the cutaneous epithelium. A median incision showed 

 that the tumour arose from the fibrous tissue layer forming the dermis; 

 there was no tendency to invade the subjacent muscles, and no 

 metastases were present. 



Sections (Fig. 5) showed that the growth consisted of a vmiform 

 reticulum of tine strands of some fibre-like substance, containing a 

 number of small rounded cells with little or no cytoplasm, which were 

 usually arranged along the fibres. These cells were seldom aggregated 

 together into masses, and no mitoses were observed. A few more 

 elongated nuclei resembling those of fibroblasts were seen, and irregular 

 spaces filled with blood corpuscles were present. 



At first sight the tumour somewhat resembled a fibrinous exudate of 

 inflammatory origin, but a more careful examination and comparison 

 of the small round cells with the normal leucocytes of the blood of the 

 whiting showed that they had little in common, and the delicate reti- 

 culum of which the growth was chiefly composed in reality bears little 

 resemblance to any exudate or tissue produced as an inflammatory 

 reaction. 



It seems probable that the tumour arose from a peculiar type of 

 pathological multiplication of connective tissue cells, or fibroblasts, 



