DEGENERATION, FATTY. [ 190 



Davallia. Sori globose, infra-marginal; 

 indusium somewhat urn- or cup-shaped, the 

 mouth truncated (figs. 161 and 162). Veins 

 pinnate. 



Fig. 161. Fig. 162. 



Davallia pyxidata. 



A pinnule with sori. A sorus with the 



Magn. 5 diams. indusium cut open. 



Magn. 15 diams. 



DEGENERATION, FATTY. The ab- 

 normal deposition of free fatty matter in the 

 histological elements of animal bodies. 



When, from whatever cause, the normal 

 functions of the morphological elements of 

 a tissue cells, or the secondary deposits 

 formed in them become languid or inter- 

 rupted, free globules of fat or oil become 

 visible in them ; and as the deposition of 

 this fatty matter increases in amount, the 

 tissue loses to a greater or less extent its 

 natural vital and physical properties ; hence 

 it is said to be in a state of fatty degenera- 

 tion. The discovery of the fatty degenera- 

 tion of tissues is probably one of the most 

 valuable fruits of microscopic study in regard 

 to medical science ; for it has shown us that 

 maladies supposed formerly to arise from too 

 great abundance of the circulating fluid, have 

 really had their origin in a decayed state of 

 the tubes or vessels in which the fluid was 

 contained ; and that the natural process of 

 human decay, as it is called, is a morbid pro- 

 cess or disease, probably to a certain extent 

 as remediable or preventible as many other 

 diseases to which man is naturally liable. 

 Here is indeed a matter of deep interest. 



In addition to the deposition of fat within 

 the elements of a tissue undergoing fatty 

 degeneration, amorphous finely granular pro- 

 teine-matters are sometimes found; occa- 

 sionally also brown, yellow, red, or black 

 granular pigment is met with, together with 

 amorphous or crystalline calcareous salts, as 

 the carbonate and phosphate of lime, &c.; 

 sometimes the fatty matter is crystalline ; it 

 then generally consists of cholesterine. 



Fatty degeneration of cells is well seen in 

 those of the liver when undergoing this 

 change. In the normal state, these, as well 



DEGENERATION, FATTY. 



as most cells, except those of true fatty tis- 

 sue, contain merely one or two very minute 

 or no globules of fat ; whilst in the degene- 

 rated tissue they contain a considerable 

 number of larger or smaller globules (fig. 

 163). At the same time, the cell-walls and 



Fig. 163. 



Cells of the human liver : a, nearly normal cells ; b, cells 

 with pigment-granules ; c, cells containing fatty matter. 



Magnified 400 diameters. 



nuclei become thinner and paler, or atro- 

 phied. A similar state to that which is 

 abnormal in man is normal in the lower ani- 

 mals. Sometimes the substance intervening 

 between cells becomes degenerated, and thus 

 we have intercellular fatty degeneration (PI. 

 30. fig. 15). Other instances of fatty dege- 

 neration are noticed under the respective 

 heads of the tissues, &c., 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- 

 flammation, the muscles, &c. 



The fatty degeneration of the capillaries is 

 represented in PL 30. fig. 13. In the larger 

 blood-vessels, when reaching a more advanced 

 degree, it forms atheroma. 



It might appear 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, thefunctions of the 

 cells, after the latter have attained their full 

 development, cease, and the cells undergo 

 degeneration and decay. 



The free fatty matter is probably derived in 

 general from the liberation of that previously 

 dissolved in the contents of the cell ; but it 

 may be produced by the formation of fatty 

 matter from the proteine or other consti- 



