The Interstitial Granules of Striated Muscle etc. 323 



low-melting fat. The faintly-refractive liposomes of this group may 

 contain olein mixed with an albumiuo-lipoid. 4. Liposomes that do 

 not stain at all in osmic acid consist mainly of some low-melting fat 

 other than olein. 5. The extent to which osmic acid stains the lipo- 

 somes depends upon the species of the animal, and its nutritive con- 

 dition. 



4. Cwpi'ic acetate (Benda's method). Benda [1900] found that 

 crystals of fatty acid are colored a bright green by neutral cupric 

 acetate. Fischler (1904) gave a modification of Benda's method by 

 which he claimed to be able to differentiate fatty acids from soaps in 

 the tissues. Klotz (1906) states that Fischler's method does not give an 

 accurate differentiation between fatty acids and soaps. For the demon- 

 stration of the fatty acids and soaps. Klotz recommends a mixture of 

 cupric acetate, formalin, chromalum, and acetic acid. Klotz' solution 

 seems to give a brighter stain, at least on cover glass preparations of 

 oleic acid and sodium oleate, than cupric acetate alone. A considerable 

 number of muscle samples were treated with the above cupric acetate 

 methods, but always with negative results. The conclusion is that the 

 liposomes do not contain either fatty acids or soaps. 



5. Neutral red and methylene blue. Schultze [1877\ stained living 

 frog and triton larvae in very dilute aqueous solutions of methylene 

 blue. He obtained rows of blue granules in the muscle fibers which he 

 stated w^ere apparently identical with Kölliker's interstitial granules. 

 ArnxDld [1900] injected methylene blue into the dorsal lymph sac of a 

 frog and found a few coarse blue gTanules in muscle fibers from the thigh. 



Albrecht found that the liposomes of fresh muscle are not stained 

 by neutral red. But if the muscle be removed aseptically and kept in 

 sterile normal salt solution 24 hours at body temperature, neutral red 

 will stain the liposomes intensely, 



Cesa-Bianchi [1910] studied the renal cells of the white mouse 



immediately after death in a 1.25 per cent solution of sodium chlorid, 



lightly colored with neutral red. A large number of fine granules are 



shown in the central half of the cells which he regards as liposomes. 



The fact that the granules are shown by neutral red seems to be the 



only evidence offered to establish their identity as liposomes, 



21* 



