MINERAL BODIES. 587 



diagonal bundles, and phosphoric acid. Next in amount we have sodium 

 and magnesium, and lastly calcium, chlorine, and iron oxide. Sulphates 

 exist only as traces in the muscles, but are formed by the burning of the 

 proteins of the muscles, and therefore occur in abundant quantities in the 

 ash. The muscles contain such a large quantity of potassium and phos- 

 phoric acid, that potassium phosphate seems to be, unquestionably, the 

 predominating salt. Chlorine is found in such insignificant quantities 

 that it is perhaps derived from a contamination with blood or lymph. 

 The quantity of magnesium is, as a rule, considerably greater than that 

 of calcium. Iron occurs only in very small amounts. The water of the 

 muscle occurs in part free and partly as imbibition water of the colloids. 

 According to the investigations of JENSEN and FiscHEB 1 only a small part, 

 a few per cent, of the total water exists in this condition. 



URANO 2 has removed the salts of the intermediary fluid (blood, 

 lymph) from frogs' muscles by treating them with an isotonic cane-sugar 

 solution (of 6 per cent) and in this manner found tKat the sodium did 

 not belong to the muscle substance itself, but to the intermediary fluid, 

 while at least a small part of the chlorine is a true muscle constituent. 

 He also calculated, from the quantity of sodium, that the intermediary 

 fluid, if it- has about the same composition as the muscle plasma, makes 

 up about one-sixth of the volume of the muscle. According to further 

 investigations of URANO the possibility of a disturbance in the osmotic 

 properties of the muscle-fibers by the sugar solution is not entirely excluded, 

 and the question whether the muscle-fibers are free from sodium or not 

 has therefore not been positively decided. FAHR'S S researches make 

 the absence of sodium in frog's muscle very probable. 



The importance of the various mineral bodies for the function of the 

 muscles has been the subject of numerous investigations and by many 

 of these we have obtained further proof, as mentioned in a previous 

 chapter, of the ion action of the electrolytes and the antagonism of 

 different ions. These researches also indicate that each of the ions 

 Na, Ca, and K plays a certain part in the maintenance of the excitability, 

 in the contraction and in the fatigue of the muscle (heart); still these 

 investigations have not led to concordant results, so that we are not yet 

 clear as to the action of these ions. Nevertheless it seems to be estab- 

 lished that the combined action of various ions is a necessity for the nor- 

 mal function of the muscles. It has also been shown that it is possible 

 to maintain the muscle (the heart) in regular activity for a long time by 

 means of a transfusion of liquid saturated with oxygen, and which con- 



1 Jensen and Fischer, Bioch. Zeitschr., 20. 



2 Zeitschr. f. Biol., 50. 



3 Urano, ibid., 51; Fahr., ibid., 52. 



