234 



THE MICROSCOPIST. 



pears to be owing to desiccation of the substance from de- 

 ficient vascular supply. It is most frequent in parts which 

 contain but few vessels, or in those in which the vessels 

 are obliterated by new growths. It was formerly believed 

 to be the product of tuberculosis, and regarded as the 

 separation of morbid matter (crude tubercle) from dis- 

 eased blood. Tubercle may undergo fatty degeneration 

 and caseation, but it is by no means true that all cheesy 

 masses are tubercular. 



Fatty degeneration in the arteries may be illustrated 

 by atheroma, beginning as a fatty metamorphosis of con- 

 nective tissue, and ending in calcification or impregnation 

 with lime salts. In the fibres of voluntary muscle the al- 

 buminous matter of the fibre is converted into fat, which 

 is seen in rows of minute globules, like strings of pearls 

 in the long axis of the primitive bundles, while the trans- 

 verse striae become indistinct (Fig. 186). 



In advanced stages of infantile spinal 

 paralysis, perhaps from inaction as well 

 as innutrition, the atrophied muscles are 

 subject to fatty degeneration, which may 

 be observed by removing small portions 

 of muscular tissue by Duchenne's trocar, 

 a sort of double needle, one part of which 

 slides upon the other, jutting against a 

 steel shoulder, so as to catch and detach 

 a small piece from a muscle into which it 

 is inserted. A microscopic examination 

 of the detached fibre will show the 

 amount of degeneration, and thus from 

 time to time the progress of disease or 

 the effects of treatment may be noted. 



In pulmonary emphysema the epithe- 

 lium is so changed by fatty degeneration 

 that the degenerated elements are better 



FIG. 186. 



Fatty degeneration 

 of striated muscular 

 fibres. 1-300. After 



ElNDFLEISCH. 



seen than the normal (Fig. 187). 



