26 PHYSIOLOGY AND HEALTH. 



40. Knowing, then, that the stomach can give out only 

 a limited quantity of gastric juice at any one time, and that 

 this fluid can dissolve only a limited quantity of food, and 

 also that this corresponds with the wants of nutriment in the 

 body, we have a measure of the amount of food which should 

 be taken at each meal; that is, as much as the gastric juice 

 can combine with in the stomach and digest. This is seem- 

 ingly unknown, and therefore no guide for us. But it can 

 be ascertained by watching the effects of eating. There is 

 an apparent understanding between the general system and 

 the healthy digestive organs ; at least, there is such a sym- 

 pathy between them that, when the one wants nourishment, 

 the other is ready to digest it. This gives the sensation of 

 hunger, which appears to be in the stomach. When this is 

 felt, the lining membrane is ready to give forth the gastric 

 juice to digest the food ; and, as long as the hungry feeling 

 continues, this fluid may flow. But when this ceases, there 

 is no more need of food, no more sensation of want, and no 

 more digestive power than sufficient to dissolve what has 

 been already eaten. Then there is a feeling of satisfaction 

 and ease in the stomach, for the appetite and craving are 

 gone. 



41. We can make use of this guide to the proper quantity 

 of food, and measure it by the quantity of gastric juice which 

 can be supplied at one time, only when we eat slowly, when 

 the morsels which we swallow, and the fluid which is to dis- 

 solve them, keep pace with each other, and meet together in 

 the stomach. By this cautious proceeding, we adapt the 

 supply of food exactly to the wants of the body, and stop as 

 soon as this want ceases. But if we eat more rapidly than 

 this, and continue to eat at this rate as long as the gastric 

 juice continues to be secreted, the food gathers in the 

 stomach faster than the digesting fluid. There is an accumu- 

 lation of food waiting to be moistened. And when, finally, as 

 much of this liquid is given out as can be afforded, there is 

 still this excess of food already in the stomach, so much more 

 than is needed or can be digested. 



