104 TRANSACTIONS LIVEEPOOL BIOLOGICAL SOCIETY. 



Fig. 1 of Plate VI represents a field of the denser 

 part of the tumour as seen under an oil-immersion lens. 

 What we have here is simply a dense plexus of blood 

 capillaries. There is no other tissue present, and the 

 vessels are gorged with blood corpuscles, so that hardly 

 anything but the nuclei of the latter embedded in an 

 almost homogeneous matrix is to be seen. Fig. 2 of the 

 same plate shows a looser region of the tumour where the 

 blood corpuscles have been partially removed in the 

 process of washing the section. The walls of the 

 capillaries can now be seen, with many contained red 

 blood corpuscles. The latter are quite normal, and so are 

 the vessels themselves. There is no interstitial tissue, 

 and the walls of the capillaries are only very slightly 

 thickened. Their calibre is, however, greater than 

 normal. 



We may, in a loose way, call this tumour a 

 haemangioma, but it is hardly the same thing as a 

 human tumour of this kind regarded as a true blastoma, 

 or malignant new growth. Undoubtedly there is growth 

 of the vessels in the sense that they are very abundant in 

 a region where they are normally scanty, and we may call 

 the structure a tumour since it has produced a very 

 noticeable external swelling. But the vessels themselves 

 are almost normal in structure — they are simply very 

 numerous. Perhaps the nearest approach to this 

 condition among human pathological ones is that of a 

 varicose vein or a haemorrhoid. Like the latter structure, 

 this tumour has probably been induced by some obstruc- 

 tion in the circulation. The condition, however, is quite 

 interesting. 



It will be noticed that secondary changes have been 

 induced in the cornea. This region of the eye in Teleost 

 fishes differs in some particulars from that in the higher 



