112 THE BODY AT WORK 



food the flow of saliva ceases. An emotion may check secretion 

 when every physiological condition is demanding it. This is 

 the explanation of the Rice Ordeal. Dry rice provokes a flow 

 of saliva in the mouth of all save the guilty man. Response 

 to mental impressions is a matter of the greatest consequence 

 in the physiology of digestion. It holds good in the case of 

 the secretion of gastric juice equally with that of saliva. The 

 sight and smell of food sets the juice flowing into the stomach, 

 and the more desirable the food, the more attractive its appear- 

 ance, the more stimulating its smell, the more rapidly does the 

 secretion flow. Here we touch upon a theme which hardly 

 needs exhaustive treatment. It is not the stoutest people 

 who eat the most, although an impartial survey of one's well- 

 nourished friends will show them to be persons who "take kindly 

 to their victuals." A small quantity of food perfectly digested 

 is more nourishing than much food which the digestive organs 

 do not efficiently prepare for assimilation. Good digestion 

 waits on appetite ; and appetite, in civilized man, is something 

 more than a mere physical need of food. The hunger which leads 

 to the bolting of food without pleasurable anticipation, without 

 mastication, without any consideration of the quality of the 

 viands, is a harmful craving which ends in imperfect assimila- 

 tion. It is more profitable to toy with a hors d'ceuvre than 

 to engulf, unthinking, a plateful of beef. But we have said 

 enough to suggest reflections to those who take no thought 

 as to what they shall eat or what they shall drink ; and few 

 who take thought need to be convinced. 



The Stomach. The sight and smell of food, its presence in 

 the mouth, and the performance of mastication, which induces 

 a secretion of saliva, gives rise at the same time to a flow 

 of gastric juice. It is psychic stimulation and the act of 

 eating which cause gastric juice to ooze from the gland-tubes 

 of the stomach at the commencement of digestion, not 

 the stimulation of nerve-endings by food which has passed 

 down the oesophagus. As a consequence of gunshot wounds, 

 or as the result of operations performed for the purpose 

 of relieving patients whose oesophagus has become blocked, 

 numerous cases have been recorded in which a fistulous 

 opening into the stomach has made it possible to study the 

 interior of this organ. Such cases present an opportunity of 



