86 PHYSIOLOGICAL CHEMISTRY. 



the filtrate into twenty times its volume of distilled water, which causes 

 a precipitation of the insoluble myosin. Allow to settle and wash three 

 times by decantation. Collect the precipitate and observe that portions 

 of it dissolve readily in ten per cent solutions of sodium chloride and 

 ammonium chloride, or in a o.i per cent solution of hydrochloric acid. 

 The solution in salt is precipitated by the addition of more to saturation. 



By this treatment with the dilute ammonium chloride solu- 

 tion nearly all of the protein of the muscle plasma may be 

 removed, leaving the stroma. It is now pretty generally rec- 

 ognized that this solution contains two substances instead of 

 one. The first of these is still called myosin, and is said to 

 make up about 20 per cent of the plasma protein, while the 

 name myogen is given to the other, constituting 80 per cent 

 of the soluble protein. Myosin is the part of the plasma which 

 coagulates or solidifies the most readily and may be separated 

 from the plasma by adding ammonium sulphate to make 28 

 per cent of the solution. On filtering, the myogen may be 

 separated by adding ammonium sulphate nearly to complete 

 saturation. The coagulation temperature of myosin is given 

 as 47, while that of myogen is 56. The former becomes 

 quickly insoluble on addition of alcohol, while myogen seems 

 to be partly soluble in alcohol. Myosin-fibrin and myogen- 

 fibrin are the names given to the coagulated forms of these 

 bodies. More will be said of these relations when we come 

 to consider the muscular substance as a whole. 



NUCLEO-ALBUMINS. 



This group contains bodies which in the pure state are rec- 

 ognized as acids. They are called nucleo-albumins because of 

 the earlier fancied resemblance to the nucleo-proteids. The 

 characteristics of the latter group, such as the presence of 

 nucleinic acid and the xanthine bases among the decomposition 

 products, are wholly wanting in the nucleo-albumins. Both 

 groups contain phosphorus, and in both cases the phosphorus 

 is separated in complex combinations on digestion with pepsin 

 and hydrochloric acid; the character of the phosphorous com- 



