GRANULES AND FAT OF STRIATED MUSCLE 



acid as used in xiltmann's method and then clear and mount in 

 balsam. The true interstitial granules are stained blue by hema- 

 toxylin or red if acid fuchsin is used. 



II. NOMENCLATURE 



In considering the significance of interstitial granules and fat 

 droplets, a clear understanding of the terminology used by various 

 authors is of importance. The true interstitial granules of 

 Kolliker correspond to Altmann's granules or 'bioblasts/ to the 

 'mitochondria' of Benda, and to the ' plasmasomes ' of Arnold. 

 Granules which do not correspond to the interstitial granules but 

 are concerned in the formation of the myo-fibrills, are also in- 

 cluded by Altmann, Benda and Arnold, as bioblasts, mitochondria 

 and plasmasomes. A part of the plasmasomes of Arnold, those 

 which are not colored by basic dyes, may represent fat droplets. 

 Benda described mitochondria in fully developed smooth muscle, 

 but thought that they do not occur in the sarcoplasm of adult 

 skeletal muscle, while Holmgren and others, using the technique 

 of Benda, have described such granules in skeletal muscle fibers. 

 The 'exoplasmic granules' (J granules and Q granules) and the 

 'endoplasmic granules' of Holmgren correspond to the 'Sarco- 

 somes' of Retzius which in turn correspond to Kolliker's true 

 interstitial granules. It is possible that Retzius and Holmgren 

 may have occasionally confused fat droplets with sarcosomes. 



Albrecht ('02) classed the interstitial granules with his 'lipo- 

 somes,' which could be demonstrated in all tissues by treating 

 fresh preparations with 5 per cent potassium hydroxide. Since 

 some of Albrecht's liposomes in striated muscle stained by acid 

 fuchsin while others blackened with osmic acid, it is clear that he 

 included as liposomes both the true interstitial granules and fat 

 droplets. Albrecht must have been mistaken in thinking that 

 all his liposomes are seen when fresh tissues are cleared in 5 per 

 cent potassium hydroxide. Fat droplets are brought out clearly 

 but the granules which stain with acid fuchsin are not apparent 

 in such preparations although they may be seen when normal 

 saline is used instead of the alkaline solution. 



