The Interstitial Granules of Striated Muscle etc. 305 



begin to reappear in advanced contraction. In the resting stage follow- 

 ing contraction the granules have all reappeared. At this stage the 

 granules are intensely stained but the fibrillae are pale. A part of the 

 content of the granules is used by the fibrillae during contraction. The 

 phase of activity of the fiber may be determined from the appearance 

 of the interstitial granules. The same changes (just described for in- 

 sects) occur in the interstitial granules of mammahan muscle during 

 contraction and relaxation, but the stages are somewhat harder to find 

 than in insects. The large Q-granules of insects are similar to some of 

 the gland granules described by Heidenhain. They increase by division 

 and do not come from the microsomes. Holmgren seems to believe that 

 these granules are cell organs. 



Gutherz [1910] disagrees with Holmgren. He finds that during con- i 

 traction the muscle fibers merely become shorter and thicker. There 

 is no change in the interstitial granules. He worked on the skeletal 

 fibers of an insect (Hydrophilus piceus). 



Arnold [1909] studied the distribution of glycogen in the cross- 

 striated muscle of the frog. Only a few frogs have muscles rich in gly- ^ 

 cogen. The glycogen is bound to the interstitial granules in the isotropic 

 band. When a large quantity of glycogen is present it extends thru the 

 Q-band. 



Knoche [1909] finds that the large interstitial granules in the wing 

 muscles of the fly (Musca) are composed of albuminous substances. He ^ 

 compares them to the crescent-shaped granules (Halbmondkörperchen) 

 described by Heidenhain in the pelvic gland of Triton. The granules 

 described are evidently the large Q-granules, tho their position is not 

 stated. Knoche inclines to the view that the granules consist of a reserve 

 food substance, but no substantial evidence is offered to support this 

 opinion. 



Regaud and Favre [1909] assign a trophic function to the inter- 

 stitial granules. They studied the muscle fibers of the tongue of a rabbit. 

 The tissue was fixed in formalin-bichromate several days. 



In a previous paper {Bell^ 1910) I have shown that the liposomes of 

 the fresh striated muscles of vertebrates can all be stained more or 

 less intensely with Herxheimer's scarlet red. A large number of gran- 



Internationale Monatsschrift f. Anat. u. Phys. XXVIII. 20 



