396 PECULIARITIES IN THE STRUCTURE 



and these only in the neighbourhood of certain parts of the 

 skeleton. It discharged no oil, but on standing a quantity of 

 watery fluid exuded, and its bulk was considerably diminished. 

 "When boiled, it dissolved into a gelatinous mass, which passed 

 in the form of a clear transparent liquid through flannel. A few 

 shreds of animal matter remained. This fluid on cooling became 

 a fine jelly, inodorous and tasteless. The greater part of this 

 tissue, then, is composed of or may be converted into gelatine* 

 There was no trace of dermis or true skin, the coloured 

 lamina of the integument appearing to be merely the super- 

 ficial layer of the peculiar cellular tissue, changed by the 

 deposition of colouring matter in the cells to adapt it to its 

 proper function. The peculiar tissue must either be looked 

 upon as the true skin itself, or more correctly it must be con- 

 sidered as the primitive nucleated vesicular tissue of the 

 embryo fish, from which the pigmentary and tubercular layers 

 of the skin have already been developed, but from which the 

 conversion into true skin has not begun, and that of the peri- 

 pheral bones has been arrested, f 



* I am indebted to Dr. Aitken for this account of the chemical constitution 

 of the tissue. 



[We have not reprinted the paragraph on the minute structure of this tissue, 

 as the examination was made with a doublet, and the description given has 

 since been superseded. We may refer to the more recent accounts of the 

 anatomy of this fish, from the dissection of specimens provided by Mr. Goodsir, 

 by Professors Cleland and Turner in the Natural History Review, 1862, and 

 to the description by Professor Harting of an Orthragoriscus ozodura in the 

 Vcrhandelmgcn der KoninMijke Akademic, Amsterdam, 1868. — Eds.] 



f Meckel, Comparative Anatomy, French edition, torn v. p. 185. Accord- 

 ing to the observations of Dr. Jacob, in the Dublin Philosophical Journal, the 

 cetacea have no dermis, except we consider, along with him, that the blubber 

 is the true skin distended with oil. The subcutaneous fat of the cetacea, how- 

 ever, differs from the gelatinous vesicular tissue of the sun-fish in having no 

 primitive cells in its constitution, consisting of common fibrous tissue inclosing 

 in its areolae fat or oil-cells. It may, nevertheless, be considered as a tissue 

 in which some of the primitive cells have been developed into fibrous tissue, 

 while others have become filled with oil. 



