14 H. HAYS BULLARD 



iiles. Occasionally the substance of the Q granules appears to 

 partially surround a fat droplet. In formalin-bichromate materi- 

 al with the Weigert and Altmann methods, vacuoles left by the 

 extraction of fat droplets during the paraffin process, are some- 

 times seen within the substance of the granule but usually the 

 vacuoles are in segment J at the poles of the granules as shown in 

 figure 5. The vacuoles thus correspond in position to the polar 

 fat granules which Holmgren describes as of occasional occurrence. 



Transverse sections show the true interstitial granules between 

 the muscle columns. When demonstrated by the formalin-bi- 

 chromate Weigert or Altmann methods, they appear rounded; or 

 flattened in transverse section. In frozen sections stained with 

 Cresylviolett or Nile blue sulphate, the granules are seen as 

 stellate bodies which may occupy almost the entire space between 

 the muscle columns (fig. 7). In describing this appearance in 

 unstained preparations, Kolliker ('88) speaks of granules provided 

 with wing shaped processes. 



When frozen sections of formalin fixed material are treated 

 with absolute alcohol and subsequently stained, Cresylviolett 

 stains the true interstitial granules (pectoral muscles of the pigeon) 

 rather faintly but the processes which give the stellate or irregular 



Fig. 3 Portion of a longitudinal section of a dark muscle fiber from the nor- 

 mal pcctoralis major of an adult cat. Fat droplets (black) are stained red by 

 Herxheimer's Scharlach 11. Membrane of Krause is situated at Z; Q, position 

 of anisotropic disc. X 1500. 



Fig. 4 Portion of a longitudinal section of a light muscle fiber from the normal 

 pectoralis major of an adult cat, stained as in figure 3; Z, position of Krause's 

 membrane; Q, position of anisotropic disc. X 1.500. 



Fig. 5 Portion of a longitudinal section of a dark muscle fiber from the normal 

 pectoralis major of a pigeon. True interstitial granules, g, (black) are stained 

 blue by a modified Weigert process. Fat droplets appear as vacuoles, a. The 

 letter m indicates muscle columns; z, Krause's membrane. X 1500. 



Fig. 6 Portion of a dark muscle fiber from the normal pectoralis major of a 

 pigeon, stained by Nile blue. Fat droplets, a, are stained red (black) ; true inter- 

 stitial granules, g, are stained blue (gray); m, muscle columns; z, Krauses' mem- 

 brane. X 1500. 



Fig. 7 Transverse section of a dark fiber and a portion of a light fiber from the 

 normal pectoralis major of a white rat, stained with Cresylviolett. Fat firoplets, 

 a, are colorless or a faint red, true interstitial granules, g, are stained blue (black). 

 The letter m indicates muscle columns. X 1500. 



