SEA-FISHERIES LABORATORY. i bef | 
division. With regard to this point, however, the results 
deducible from the tissue are unsatisfactory, since no 
mitotic figures can be seen. A small artery is shown near 
the bottom of fig. 2, and round this there is an 
astonishing multiplication of the connective tissue cells, 
so that this part of the section has an appearance almost 
like that of the interstices of a lymphatic gland. In its 
proliferating zone the sarcoma is of very mixed character, 
and it is only in the older regions that it assumes a 
spindle-cell character. 
Perhaps the most convincing evidence of the 
malignancy of the growth is afforded by a study of the 
epidermis over the marginal parts of the tumour. Fig. 4, 
Pl. V, represents a part of the normal epidermis, and is 
reproduced for the purpose of comparison with fig. 6, 
which represents a part of the epidermis covering the outer 
zone of the actual tumour. Here the cells of the sarcoma 
have invaded, and are infiltrating the superficial layer of 
the skin. In normal conditions the cells of the latter are 
in contact with each other except for the very short 
‘* prickles ’’; but in the invaded parts the epidermal cells 
become dwarfed, are separated from each other by 
relatively wide spaces, and the protoplasmic filaments 
become drawn out, or break through, so that the cells may 
become isolated from each other. Intercalated among 
them are cells which are similar to those of the tumour at 
its zone of proliferation; and may even be loaded with 
melanin granules. The epidermis gradually thins out 
over the older parts of the growth, and then the latter 
becomes more exposed to mechanical or possibly septic 
injury. 
It seems quite clear that the tumour is a really 
malignant one, and does not belong to the class of healing 
or regenerative new tissues which one often finds in fishes 
I 
