46 GENERAL HISTOLOGY. 



Fatty degeneration in the coats of arteries may lead to 

 atheroma, which begins as fatty metamorphosis and ends in 

 calcification. In fatty degeneration of voluntary muscle the 

 metamorphosed albuminous fiber is seen as rows of minute 

 globules of fat in the long axis of the primitive bundles, while 

 the transverse striae become indistinct. 



In pulmonary emphysema the epithelium is so changed that 

 the fatty degenerated elements are more conspicuous than the 

 normal. Fatty metamorphosis is the regular mode of decom- 

 position for tissues liable to rapid change, as epithelium. De- 

 creased nutrition produces it, especially in non-vascular tis- 

 sues, as cartilage and the transparent media of the eye. 



Softening of the brain is largely due to fatty degeneration. 

 Acute cases may be caused by embolism or thrombosis, in- 

 terfering with nutrition. White softening is a chronic condi- 

 tion of old age from the gradual diminution of blood supply. 

 Yellow and red softening depend on the proportion of blood 

 pigments present. In all these cases accumulations of fat are 

 present between the nerve fibers. 



2. Amyloid degeneration is known also as waxy or larda- 

 ceous degeneration, and vitreous swelling. It is due to nutri- 

 tive disturbance, and, next to fatty metamorphosis, is the most 

 frequent and most important degeneration. It is a chronic 

 change of tissue, producing a peculiar homogeneous trans- 

 lucent albuminous substance, which becomes brownish red 

 (like mahogany) on the application of iodine, and violet on 

 adding sulphuric acid. 



The arnyloid cell is larger than normal, and deformed. 

 Such cells often coalesce. This form of degeneration occurs 

 most often in the small arteries and capillaries, more rarely 

 in interstitial connective tissue. 



Corpora amylacea are often ranked with lardaceous degen- 

 eration, since they become blue by treatment with iodine and 

 sulphuric acid. They are small round or oval bodies, homo- 

 geneous or laminated, found in the prostate gland, the ven- 

 tricles of the brain, and other parts. Some of the tube casts 

 of the kidney resemble them. 



3. Mucous degeneration is a transformation of albuminoid 



