572 MUSCLES. 



variation in this quotient after different foods. According to SALKOWSKI, 

 of the total nitrogen of beef 77.4 per cent was insoluble proteins, 10.08 

 per cent soluble proteins, and 12.52 per cent other soluble bodies. 

 FRENTZEL and SCHREUER l find that about 7.74 per cent of the total 

 nitrogen belongs to the nitrogeous extractives. 



There exist complete investigations by KATZ 2 as to the quantity 

 of mineral constituents of the muscles from man and animals. The 

 variation in the different elements is considerable. Pork is much richer 

 in sodium as compared with potassium than other kinds of meat. The 

 quantity of magnesium is greater, and often considerably greater, than 

 calcium in all kinds of flesh investigated, with the exception of the 

 haddock, the eel, and the pike. Beef is very poor in calcium. Potassium 

 and phosphoric acid are the most abundant mineral constituents of all 

 flesh. 



Non-striated Muscles. 



The smooth muscles have a neutral or alkaline reaction (DuBois- 

 REYMOND) when at rest. During activity they are acid, which is inferred 

 from the observations of BERNSTEIN, who found that the almost con- 

 tinually contracting sphincter muscle of the Anodonta is acid during 

 life. The smooth muscles may also, according to HEIDENHAIN and KuHNE, 3 

 pass into rigor mortis and thereby become acid. A spontaneous but 

 slowly coagulating plasma has also been observed in several cases. 



In regard to the proteins of the smooth muscles we have the earlier 

 accounts of HEIDENHAIN and HELWio; 4 but they were first carefully 

 studied according to newer methods by MUNK and VELicni. 5 These 

 experimenters prepared a neutral plasma from the gizzard of geese, 

 according to v. FURTH'S method. This plasma coagulated spon- 

 taneously at the temperature of the room, although slowly. It con- 

 tained a globulin, precipitated by dialysis, which coagulated at 55-60 

 C. and also showed certain similarities with KUHNE'S myosin. A spon- 

 taneously coagulating albumin, which differed from myogen (v. FURTH) 

 by coagulating at 45-50 C., and which passes by spontaneous coagula- 

 tion into the coagulated modification without a soluble intermediate 



1 Argutinsky, Pfluger's Arch., 55; Kohler, Zeitschr. f. physiol. Chem., 31; Sal- 

 kowski, Centralbl. f. d. med. Wissensch., 1894; Frentzel and Schreuer, Arch. f. (Anat. 

 u.) Physiol., 1902; Miiller, Pfluger's Arch., 116. 



2 Pfluger's Arch., 63. See also Schmey, Zeitschr. f. physiol. Chem., 39. 



3 Du Bois-Reymond in Nasse, Hermann's Handb., 1, 339; Bernstein, ibid., Heiden- 

 hain, ibid., 340, with Hellwig, ibid., 339; Kiihne, Lehrbuch, 331. 



4 Heidenhain in Nasse, Hermann's Handb., 1, 340, with Hellwig, ibid., 339; Kiihne, 

 Lehrbuch, 331. 



5 Munk and Velichi, Centralbl. f. Physiol., 12. 



