ATROPHY OF THE ORGANS OF THE LARVAL FROG. 



153 



been described as a "chromatolysis," but the dark masses running 

 transversely over the muscle bands are'depositions of fats bearing 

 unsaturated fatty acids (oleic) which stain with the osmium 

 tetroxid used in fixation. Willard and Guenther in unpublished 

 investigations upon the micro-chemistry of degenerating muscle 



FIG. 2. Section of similar stage, same species, showing peripheral tissues. 

 Not all of the intensely black areas are those of chromatolysis, for the osmium 

 stains those neutral fats containing unsaturated fatty acids, such as oleic. 



fibers find similar conditions in mammalian muscles permitted to 

 degenerate after severing the innervation; a change in the distri- 

 bution of neutral fats occurs involving the grouping of these com- 

 pound s into masses, or droplets. 1 The significance in the present 



1 There is no evidence of an infiltration of fat, but rather of a simple process of 

 accumulation of fats already present in diffused form. 



