EXAMINATION OF MUSCULAR TISSUE. 23 



The residue of meat remaining after pressing is broken up, 

 heated to boiling with water in a tin dish, and the water 

 together with the fat floating on it is poured off. This opera- 

 tion is repeated once more and then the mass is filtered 

 through muslin. The residue may be used for digestion 

 experiments. 



II. DETECTION OF THE PRINCIPAL PROTEIDS IN MEAT. 



Meat extracted with cold water. 



Filtrate contains soluble Residue may be used for the 



proteids. preparation of myosin. 



Mix 100 g. of finely ground meat with 300 cc. of water, 

 stir thoroughly, let stand one to two hours, pour the mixture 

 through a muslin filter and squeeze out the residue with the 

 hand. The filtrate is colored red (from the haemoglobin) and 

 is usually somewhat cloudy on account of the fat and small 

 particles of muscle. In order to make it clear it is filtered 

 through paper. 



1. Filtrate. 



(a) Testing the Reaction. Tested with sensitive litmus 

 paper the filtrate reacts acid in consequence of its containing 

 primary potassium phosphate (KH 2 P0 4 ). The acid reaction 

 becomes stronger on keeping the meat on account of the 

 formation of lactic and other acids. 



(b) A portion of the filtrate is slowly heated in a test- 

 tube in which a thermometer is placed. For this purpose 

 put the test-tube in a beaker half filled with water and heat 

 the beaker on the wire gauze. By frequently stirring the 

 water with a glass rod, on the under end of which is a piece 

 of rubber tubing, the even distribution of the temperature 

 may be accomplished. Even at a slight elevation of tem- 

 perature, usually at 55 to 56, coagulation occurs, the fil- 



