GRANULES AND FAT OF STRIATED MUSCLE 27 



albuminous substance. He states that the granules have a cap- 

 sule which stains with acid fuchsin but he does not give the details 

 of his technique. As has been previously mentioned, the entire 

 granule is readily stained in formalin-bichromate material with 

 Altmann's acid fuchsin. Employing material from the pectoral 

 muscles of the pigeon and bat and from the wing muscles of in- 

 sects, I have also found that Altmann's acid fuchsin stains the 

 granules after simple formalin saline fixation (paraffin process) 

 the potassium bichromate being unnecessary. The fragmented 

 granules in alcohol-fixed material are not stained by Altmann's 

 acid fuchsin. •> 



Smith and Mair ('11) find that lecithin and sphingosine stain 

 readily with acid fuchsin both before and after the action of potas- 

 sium bichromate. They think the presence of either of these 

 substances would explain the staining of Altmann's acid fuchsin 

 granules. Pure lecithin, according to these observers, does not 

 stain by the "Weigert process, but they add that it stains readily 

 if it has the slightest admixture of cholesterin. Faure-Fremiet, 

 Mayer and Schaeffer ('10) state that lecithin and other lipoids 

 fail to stain by the Weigert process, but may be stained by hema- 

 toxylin if preceded by iron. alum. Since the true interstitial 

 granules stain readily by the Weigert process, the iron alum not 

 being necessary, we may conclude that if the staining of these 

 granules depends largely on lecithin, as suggested by the acid 

 fuchsin method, the lecithin is not in a pure state. 



Fatty acids, according to Smith and Mair ('11), do not stain 

 with acid fuchsin either before or after the action of potassium 

 bichromate. Faure-Fremiet, Mayer and Schaeffer ('10), on the 

 other hand, find that fatty acids are faintly stained by this dye, 

 both before and after bichromating, presumably with greater 

 intensity in the latter case, for they think that the presence of 

 fatty acid would account for the staining of Altmann's granules. 

 I have stained tissue paper smears of oleic acid (Kahlbaum) after 

 treatment for a variable length of time (one to six days) in satu- 

 rated potassium bichromate. The smears were stained with acid 

 fuchsin either Altmann's mixture or in alcoholic solution, heating 

 according to- the method of Altmann. The droplets were stained 



