GRANULES AND FAT OF STRIATED MUSCLE 23 



that the partial disappearance of the granules from alcohol fixed 

 material may be due to the solution of a fatty substance which 

 can be rendered insoluble by the action of potassium bichromate. 

 It was found, however, that the granules of material fixed in 20 

 per cent formalin show no more shrinking after the paraffin pro- 

 cess than do those of formalin fixed material which has been mor- 

 danted in potassium bichromate before the alcohol and xylol pre- 

 ceding embedding. Thin paraffin sections were also washed in 

 several changes of hot ether four to six hours and subsequently 

 examined under the microscope after staining with acid fuchsin 

 or hematoxylin. _ The fat ^extraction by this method is considered 

 more complete than by the Soxhlet's apparatus as ordinarily 

 employed. Ether does not dissolve the true interstitial granules 

 from paraffin sections of formalin fixed material taken from the 

 pectoral muscles of the pigeon. The partial disappearance of 

 the granules, from alcohol fixed material, takes place in the alcohol 

 and xylol, and the subsequent treatment with ether appears to 

 have little effect. If we suppose that the shrinkage or disappear- 

 ance of the granules in alcohol or xylol is due to the extraction 

 of a fatty substance, it is also necessary to suppose that the fatty 

 substance is in part rendered insoluble in alcohol, xylol and ether 

 by the coagulative action of the formalin on the non-fatty sub- 

 stance of the granules. As will be seen below, however, staining 

 with Cresylviolett indicates that the true interstitial granules are 

 soluble in alcohol to a very considerable extent even in formalin 

 fixed material 



3. Results with Cresylviolett R R, Cresylechtviolett, and Nile blue 

 sulphate. Krause ('11) recommends Cresylviolett R B in dilute 

 aqueous solution for demonstrating the interstitial granules in 

 fresh tissue. I have used Cresylechtviolett and Cresylviolett 

 R R which are apparently similar to the dye employed by Krause. 

 The fat droplets are not stained to any considerable extent by 

 Cresylviolett. Occasionally they show an exceedingly faint red 

 color or a more intense peripheral blue staining but usually they 

 are left colorless. 



As mentioned above, the true interstitial granules are par- 

 tially dissolved by water. Since this is the casej one should 



