114 APPLIED PHYSIOLOGY 



shellfish are of the same nature. The muscles form the 

 lean part of meat, but nearly every part of the animal is 

 sometimes used as food. Average meat consists of 



Water 65 per cent. 



Albumin 17 ' 



Fat 14 



Mineral matter 4 " 



Albumin is the principal part of meat. Beef has high 

 food value; mutton, fowl, and game rank next, in the 

 order named. 



r >< 170. Digestibility of meat. Meat varies greatly in 

 composition and digestibility. While man cannot digest 

 stringy connective tissue and tough skin at all, yet good 

 meat ranks next to milk and eggs, and exceeds all forms 

 of vegetable food in all the four points of digestibility. It 

 requires a small outlay of time and energy in its digestion, 

 and its oxidation develops a large amount of heat and 

 energy. It does not easily ferment, and only about one 

 thirtieth remains undigested. 



Meat is often salted or smoked or dried, or prepared in 

 other ways so that germs of fermentation or decay will not 

 grow in it, and thus it can be kept for a long time. When 

 thus prepared, its fibers are partly coagulated and har- 

 dened, so that the gastric juice cannot penetrate them 

 readily. The digestibility of such meat is greatly impaired. 

 The toughness of meat is due to strings of connective tis- 

 sue, which are digested with difficulty and yield little heat 

 and energy to the body. Tender meat consists almost 

 wholly of muscular fibers, which are the main nutritive 

 parts of most meat. Since meat contains no starch or sugar, 

 some must be added in order to make it a perfect food ; 

 and, very properly, bread is generally used. 



