PHYSIOLOGICAL 107 



movements of the living body. The muscular tissue itself, 

 which constitutes by far the greater part of the substance of 

 the meat, consists of striated fibres which taper at both ends. 

 Each of these fibres is a single cell provided like other cells with 

 a nucleus and enclosed by a membrane forming the wall of the 

 muscle fibre. The muscle fibres running parallel to one another 

 are united into bundles by connective tissue, and the bundles 

 themselves are further bound together to form the entire muscle. 

 The meat derives its red colour from the haemoglobin or red 

 pigment of the blood. 



Butchers' meat in the more general sense consists of the 

 prepared carcases of oxen, sheep, and pigs, and of the young of 

 these animals, but in the present work we are restricted to the 

 consideration of beef -production. In the living animal, two 

 phenomena contribute to this object, growth and fattening. In 

 a general popular sense these terms are understood, but they 

 require exact definition or at any rate description. Both pro- 

 cesses involve the addition of new tissue, that is of living matter 

 or protoplasm, but whereas the term growth is usually confined 

 to that increase which is correlated with the development of 

 the individual from birth to maturity, fattening is a process 

 which may be reversed many times over at any period through- 

 out life, a fat animal becoming lean and a lean animal fat. 

 Strictly speaking the term fattening ought to be restricted to 

 the addition of adipose tissue, but it is often used much more 

 loosely so as to include the putting on of more muscle when that 

 process is accompanied by an increasing accumulation of fat. 

 In a similar way the term growth is sometimes employed to 

 express the development of muscular tissue (that is of meat) 

 even late in life when skeletal and developmental growth has 

 ceased. Such addition of muscular tissue, as is well known, is 

 the usual result of increased use or exercise which generally 

 implies also an increase in the food consumed. 



In cattle the skeleton or bony frame gradually goes on growing 

 until a certain age, usually about five years, after which time it 

 remains the same. In oxen, as a result of castration, the limb 

 bones go on growing for a somewhat longer period, since one 

 of the effects of the removal of the generative organs is to 



