The Puffy Cliaiigcs. 



193 



the nuclei are obscured or destroyed, and the ciuthnes uf the cell> 

 irres-ular. The difference from albuminous ,G:ranules may l)e 

 recognized in teased preparations by the f.ict lliat the fat droplets 

 are not aft"ected by acetic acid and alkalies, and in microscopic 

 sections, which have been carried through alcohol and ether, 

 chloroform or xylol, by the removal of the fat by these reagents, 

 the places where it was present in the protoplasm consequently ap- 

 pearing as vacuoles (small holes or spaces — foam structure of the 



Fig. 25. 



Nodular fatty liver of dog; portion of a section under low magnitication. (After 



Rauscher. ) 



cells). An excellent method of demonstrating the fat microscopic- 

 ally is by staining with Sudan III (an aniline dye), which may 

 be employed in teased tissue or frozen sections after hardening 

 with formol, but not after the use of fat solvent reagents, the fat 

 droplets being tinged an orange yellow color by the dye. Fat may 

 also be fixed by osmic acid, which makes it black and renders it 

 insoluble in alcohol, ether and chloroform ( it is. however, still 

 soluble in benzine, toluol and xylol — Diirk). 



Fatty degeneration may be well seen in muscle fibres, in which 



