314 E. T. Bell, 



acetic acid than the contractile substance. As to the large Q-granules 

 in the wing muscles of insects he states (1887) that chemically they are 

 unlike any known substance. He succeeded in dissolving them only by 

 boiling the muscle with concentrated potassium hydroxid, and treat- 

 ment twenty-four hours with cold concentrated nitric acid. Kölliker 

 was sure that the "true" interstitial granules are not composed of fat, 

 but he believed that the fat droplets are derived from them. He 

 was evidently sometimes unanble to distinguish "true" interstitial granu- 

 les from fat droplets (1889), He states definitely that the true inter- 

 stitial granules of neither frogs nor insects are soluble in alcohol or ether. 



Several observers are in agreement with Kölliker that true inter- 

 stitial granules are insoluble in alcohol and ether. Usually however 

 they were not dealing with liposomes. 



Knoll [1880 — 1881] found that practically all the interstitial gran- 

 ules of the heart muscle of pigeons disappear after treatment of the 

 tissue two days in absolute alcohol and one day in ether. 



Holmgren [1907 — 1908] states that usually the interstitial granules 

 cannot be shown if the tissues be fixed in Carnoy's fluid (alcohol, 

 chloroform, and acetic acid), except in contracted fibers. 



A large number of teased preparations and frozen sections of fresh 

 muscle from various vertebrates have been treated with absolute alcohol. 

 It has been invariably found that after a few hours extraction nothing 

 can be shown in the tissue with any fat stain. Often a well teased 

 specimen or a thin section is completely extracted in ten or fifteen 

 minutes. It seems certain that at least the stainable substance in the 

 granules is completely dissolved by absolute alcohol in a very short 

 time. If the tissue be examined in water or very dilute potassium 

 hydroxid after the alcohol extraction, a few fibers are occasionally found 

 in which shrunken remnants of a few granules are to be seen ; but in 

 the great majority of the fibers no trace of any of the granules is to be 

 found. Nearly all the granules seem to be completely dissolved by ab- 

 solute alcohol, but some of them may leave a small residue. 



It is possible that some of the remnants found after the alcohol 

 extraction are portions of pigment granules. The relation of pigment 

 granules to liposomes has not been determined. 



