186 OKIGIKAL ARTICLES. 



size. This fluid heated, either alone, or with nitric acid, gave a 

 flocculent albuminous precipitate. It contained no oil, and exhibited 

 when allowed to cool, after being heated, no tendency to gelatinizatiou. 

 Wlieu portions of the white structure were heated in their own 

 fluid, in a water bath, and then allowed to cool, gelatinizatiou took 

 place, which was due, not to any peculiarity of the fluid, but to the 

 chemical composition of the opaque white substance, in the inter- 

 spaces of wliich the fluid was infiltrated. Other portions of the skin 

 placed under an exhausted receiver, along with sulphuric acid, 

 shrivelled up to flake-like shavings of glue. The white mass was 

 thus shown to belong to the gelatine-yielding structures, and to have 

 no similarity hi composition to the blubber-yielding integument of 

 the cetacea. 



From the chemical examination it was probable that this 

 structure was to be regarded as cutis, a supposition which was 

 confirmed by a microscopic examination. When small portions of 

 the cutis were examined in the fresh state, under a magnifying powei' 

 of 200 diameters, they were found to be composed of a closely arranged 

 network of fine fibres, the exact characters of which could not be 

 clearlv studied until they were separated by dissection ^vith needles. 

 (PI. VI. fig. 4.) It was then seen that the fibres presented 

 certain special peculiarities, which distinguished them from the fibres 

 of ordmaiy connective tissue. Instead of being collected in fibril- 

 lated bundles, each fibre possessed a distinct form and outline, (some 

 being almost twice as broad as others), and extended for some 

 distance, pursuing either a slightly wavy, or a curling tortuous 

 course. From the veiy curly nature of many of these fibres I 

 thought that they represented the elastic element of the cutis, but, 

 on the addition of acetic acid, they disappeared in the same manner 

 as the undulating fibres. This observation was repeated on fibres 

 taken from various parts of the cutis, so that it may fau-ly be stated 

 that the elastic element was either altogether absent from the skin 

 of this fish, or was at a minimum. Throughout the entire tliickness of 

 the cutis, the fibres presented a well-marked reticulated arrangement, 

 which distinguished them from that which is generally described to 

 exist in the sldn of fishes, where the fibres ai'e mostly disposed in 

 bundles parallel to the free surface, being crossed only at compara- 

 tively wide intervals by bundles possessing a vertical direction. In 

 the meshes of this reticulation the abundant fluid of the skin was 

 lodged. Numbers of small, ovoid, elongated, sometimes roundish 

 cells, some of which possessed a single, others two or more nuclei, 

 were also contained in these meshes. (Fig. 4.) These cells were 

 visible, not only in the fresh skin, but after the addition of acetic 

 acid, and even in those slices of the skin which had been digested in 

 the water bath. From the close relation which these cells had to the 

 fibres amongst which they were imbedded, I thought it likely, that, 

 by a careful examination, it might be possible to see processes 

 springing from them in such a manner as to produce that stellated, or 



