DEGENERATION, FATTY. [ 238 ] 



DELESSERIACEyE. 



nuclei become lliinner and paler, or atro- 

 phied. A similar state to that T\-hich is 

 abnormal in man, is normal in the lower ani- 

 mals. Sometimes the substance intervening 

 between cells becomes degenerated^ and thus 



Fi^. 160. 



CeEs of the human liver; a, nearly normal cells; 6, 

 cell with pigment granules ; c, cells containing fatty 

 matter. 



Magnified 400 diameters. 



we have intercellular fatty degeneration 

 (PI. 38. tig. 16). Other instances of fatty 

 degeneration are noticed under the respective 

 heads of the tissues kc:, as the Graafian 

 vesicles and the cells of the corpora lutea 

 (Ovary), the epithelia of the mucous and 

 serous membranes, and of the various glands, 

 the vessels, the exudation-corpuscles of in- 

 ilammation, the muscles, &c. 



The fatty degeneration of the capillaries is 

 represented in PI. 38. fig. 13. In the larger 

 blood-vessels, when reaching a more ad- 

 vanced degree, it forms atheroma. 



It might appe.ar paradoxical to regard the 

 presence of numerous fat-globules, in such 

 instances as the cells of cancer, and the 

 exudation-cells of inflammation, where the 

 vital processes are so evidently augmented, 

 as indicating a state of degeneration. But in 

 these, as in other instances, the functions of 

 the cells, after the latter have attained their 

 full development, cease, and the cells un- 

 dergo degeneration and decay. 



The free fatty matter is probably derived 

 in general from the liberation of that pre- 

 viously dissolved in the contents of the 

 cell ; but it may be produced bj^ the for- 

 mation of fatty nuitter from the proteine or 

 other constituents of the cell-contents. It 

 is curious that portions of the llesh and 

 other proteine-components of one animal, 

 when kept in the peritoneal cavity of another 

 living animal, will undergo fatty degenera- 



tion. The formation of adipocere seems to 

 be an instance of post-mortem fatty dege- 

 neration. 



Amyloid degeneration is noticed under 

 Amyloid. 



BiBL. Virchow, Path. Cell. 1861; Wedl, 

 Path. Hist. ; Forster, Spec. Path. Anat. ; 



d. Wiss. z. Gottin- 

 ix. 309); Green, 



Wagner, Nach\ d. Ges 



qen, 1851 {Chem. Gaz 



'Path. 31, 1871 ; Riudfleisch, Lehvh. Geweh. 



187-8, 46. 



DELAVA'LIA, Brady.— a genus of En- 

 tomostraca, order Copepoda. 



D. imludris. Northumberland. 



BiBL. Brady, Trans. XorthuinherlandSi-c., 

 Si Copepoda (Ray Soc). 



DELESSE'PJA, Lamx.— Agenus of De- 

 lesseriacete (Florideous 

 Algae), consisting of 

 sea-weeds with a flat, 

 membranaceous, rose- 

 coloured frond, having 

 a percurrent midrib, 

 growing on rocks or 

 on other larger Algte, 

 mostly from 2 to 8 

 inches high. Six spe- 

 cies are described as 

 British, most of them 

 common. The leaf-like 

 lobes of the frond arise 

 from a kind of stalk, or 

 from the midribs of 

 older lobes. The tex- 

 ture is densely paren- 

 chymatous throughout. 

 D. sanyuinea (PI. 4. fig. 5) ripens its fruit 

 in the winter ; and then the membranous 

 part of the fronds decays, leaving the midribs 

 clothed with tufts of the sporophijUs or leafy 

 lobes containing the tetraspores (fig. 161), 

 and stalked coccidia cont.aiuing the spores. 

 The fructification is somewhat similar in 

 D. alata, while in D. sinuosa the coccidia 

 are immersed in the frond, and the tetra- 

 spores in cilia-like processes fringing its 

 margin ; and in 1>. Hypocjlossum the coc- 

 cidia are seated on the midi'ib, and the 

 tetraspores arranged in longitudinal linear 

 rows like sori on each side of the midrib. 



BiBL. Harvev, Mar. Algce, 113, pi. 16 A; 

 Phyc. Brit, pis! 2, i>6, 83, 151, 247, 259; 

 Greville, Alt/. Brit. pis. 72-74, 76. 



DEL1-:SSERIA'C1LE.— A family of Flo- 

 ridete. Rosy or purplish red, or blood-red 

 sea-weeds, with a leafy, or rarely filiform, 

 areolated, inarticulate frond, composed of 

 polygonal cells. Lobes of the frond deli- 



Delesseria sanguinea. 

 Midribs of fronds in win- 

 ter bearing sporophylls. 

 If at. size. 



