300 E. T. Bell, 



muscles of insects. He gives figures of muscle fibers from Dytiscus and 

 thejiumble bee (drawn in one-half per cent sodium clilorid) showing the 

 rows of large interstitial granules. The figures show that these large 

 granules are all apparently in the Q-band. He states that 

 chemically the granules are unlike any known substance. They 

 consist of a soft substance, since they swell in water and shrink 

 in alcohol; but they are very difficultly soluble. In water they 

 swell markedly to form vesicles with a delicate but distinct wall, the 

 contents collecting as a cresent on one side and undergoing partial 

 solution. Dilute acids and alkalies cause the granules to swell and 

 fade but do not dissolve them. Alcohol, ether, gastric juice, and trypsin 

 have little effect. The granules were dissolved only by boiling the muscle 

 with concentrated potassium hydroxid, and treatment 24 hours with 

 cold concentrated nitric acid. Besides these typical granules there 

 occur in the wing muscles of insects also true fat droplets which appear 

 as dark refractive droplets after the addition of acids or alkalies, and 

 dissolve in ether. Usually the fat droplets are few but cases occur, 

 especially it seems in animals kept a long time in the room (Dytiscus), 

 in which they are present in unusual n umbers and the typical granules 

 are few or absent. The fat droplets in the fibers are to be regarded as 

 food material. 



Kölliker [1889] figures and describes the interstitial granules of 

 vertebrates and insects. They are present in all classes of vertebrates 

 and insects, sometines in enormous numbers. They probably change 

 into the long-known dark (fat ?) droplets of certain animals (winter frog, 

 certain muscles of fishes). 



Retzius [1890] describes the interstitial granules (which he calls 

 sarcosomes) in both vertebrate and invertebrate muscle as specific 

 constituents of the sarcoplasm, not identical with fat droplets. He 

 agrees with Krause that the "Nebenscheibe" is formed by a row of 

 interstitial granules. The granules are often connected by delicate 

 threads. In vertebrates the granules have a difinite relation to Krause's 

 membrane. 



Knoll [1891] published an extensive paper in which the distribution 

 of the dark and light muscle fibers in various vertebrates is given in 



