THE CHEMICAL COMPOSITION OF MUSCLE. 77 



stomach and passed along the intestines, whether we 

 think about it or not. 



The chemical composition of muscle. Muscle contains 

 about 75 per cent, of water ; and a considerable quantity 

 of salines. Living, resting muscle is alkaline to test 

 paper ; hard- worked or dying muscle is acid. Its chief 

 organic constituents are proteid or albuminous substances 

 (p. 21), and of these the most abundant in a per- 

 fectly fresh muscle is myosin. Soon after death the 

 myosin clots. Dilute acids dissolve myosin and turn it 

 into syntonin, which used to be thought the chief pro- 

 teid of muscle. 



Beef tea. When lean meat is heated its myosin is 

 converted into a solid insoluble substance much like the 

 white of a hard-boiled egg. Hence, when a muscle is 

 boiled most of its proteid is coagulated and stays in the 

 meat instead of passing out into the soup. Even if beef 

 be soaked first in cold water this is still the case, as myo- 

 sin is not soluble in water.* It follows that beef tea as 

 ordinarily made contains little but the flavoring matters and 

 salts of the beef, and some gelatin dissolved out from the 

 connective tissue of the muscle. The flavoring matters 



What proportion of water docs muscle contain? What other in- 

 organic compounds do we find in it? What is the reaction of living 

 muscle? How is this changed by work or death? What are its main 

 organic constituents? Nam'! the most abundant of these? What 

 change occurs in it after death? What is syntonin? 



What happens to the myosiu when muscle is heated? When we 

 boil meat does its myosin become dissolved in the soup? Can we get 

 the myosin out of beef by soaking it in cold water? What things are 

 found in ordinary beef tea? 



* To get over this difficulty, various methods of making beef tea have been 

 suggested, in which the chopped meat is soaked an hour or two in strong brine 

 or in very dilute muriatic acid. In these ways the myosin can be dissolved out 

 of the beef; but the product has such an unpleasant taste that no one is likely 

 to swallow it, and least of all a sick person. 



