106 PHYSIOLOGICAL 



of calories; there are other factors of importance, both physio- 

 logical and psychological, which must be taken into account; 

 even the palatability of a food is not a matter to be dismissed 

 lightly, for palatability is an assistance to appetite, and the 

 existence of appetite is functionally correlated with the secretion 

 of some at least of the digestive ferments. Thus the experi- 

 ments of the distinguished Russian physiologist Pavlov 1 showed 

 that the sight, smell, and taste of food, acting reflexly through 

 the nervous system, are the exciting cause of the secretion of 

 the saliva and the gastric juices, and that the glands producing 

 these digestive fluids are brought into functional activity under 

 the stimulating influence of appetite before the food is swallowed 

 or even before it enters the mouth. 



Now of the food substances which enter into the diet of a 

 normal man in a temperate climate, meat is one of the most 

 important. This may be partly the result of habit, for meat is 

 not an irreplaceable necessity (at any rate for many individuals) 

 as successful vegetarianism has proved. But although it is 

 probably true that in pre-war days the amount of meat consumed 

 by certain classes of society was wastefully excessive, it is in- 

 disputable that for the normal man a moderate allowance eaten 

 daily is an unqualified advantage, since its effect is to decrease 

 the labour of digestion and to reduce the faecal residue. The 

 desirability therefore of ensuring a sufficient supply of home- 

 grown meat is a matter of the greatest national importance from 

 the point of view of preserving the strength of the people and 

 maintaining in times of crisis and difficulty their morale in full 

 measure. 



Meat, in the purely restricted sense of the term, consists of 

 muscular tissue, together with other tissues which are closely 

 associated with it, that is to say the connective tissues which 

 bind the muscle fibres together, the slight amount of fat which 

 is deposited in the connective tissue, the blood vessels which 

 supply nourishment and carry away the waste products, and 

 the minute nerves which connect the muscles with the brain 

 or spinal cord, and provide a co-ordinating mechanism for the 



1 Pavlov, Tke Work of the Digestive Glands, translation by W. H. 

 Thompson, London, 1902. 



