470 Proceedings of the Boyal Physical Society. 



Description of Plate XX II I. 



FIG. 1. 



Section of small portion of capsule and one of the larger sequestra, stained 

 Vfith osmic acid ( x 60). 



{a) Sequestrum composed of vitreous masses of muscular fibres ; the areas 

 are well seen, and the fragmentation is well marked. 



(J) Thin layer of connective tissue in immediate contact with the sequestrum. 

 This is granular and fatty, and in many cases consists merely of a mass of 

 dihris. Outside this is a well-defined space or fissure. 



(c) Layer of vascular granulation tissue with larger cells near the fissure, 

 and with well-marked vascular loops throughout. Beneath this the tissue 

 is denser, cells are more fusiform or branching, and larger vessels are 

 found. 



{d) Fibrous or fibro-cellular layer, in which are enclosed numerous atrophied 

 muscular fibres, represented by the dark patches. 



(e) Vitreous muscular fibres outside the capsule altogether. 



FIG. 2. 



Longitudinal section of some of the hyaline muscular fibres, in the earlier 

 stages of the process, taken from just outside the capsule. Stained with 

 osmic acid ( x 400). 



{a) Striped muscular fibre, quite normal in appearance. 



(&) Portion undergoing the vitreous or hyaline fragmentation. In this mass 

 small globules of fat, stained black with osmic acid, may be seen. 



(c) Fibre in which fragmentation and vitreous degeneration is more general, 



{d) Inter-muscular connective tissue, only slightly increased in quantity. 



XLI. Caseous Ulcer in Shin of Cod. By G. SiMS Woodhead, 

 Esq., M.D., F.RC.P.Ed. [Plates XXIIL, XXIV.] 



(Read 20th May 1885.) 



In a previous paper on Degeneration in the Muscles of a 

 Fish, it was pointed out that there was first a vitreous change, 

 which, however, was almost invariably followed by a true 

 caseation. Through the courtesy of Ben. Peach, Jun., Esq., 

 E.E.G.S., I am enabled to place before the Society a very 

 good example of caseation in the skin and deeper tissues of a 

 cod, leading to ulceration, destruction of the periosteum, and 

 complete disorganisation of the joints at the bases of the 

 fin rays. 



The portions of the fish sent to me were a pectoral and a 

 ventral fin cut out with a penknife from the left side of a 



