NEEDS OF THE ANIMAL 359 



By cutting up the stomach of an animal and pouring 

 glycerin on it, we can extract the ferments or digestive 

 juices. In the first place we may use these to partly 

 digest our food before we eat it (predigested foods). 

 Second, we may take them in small doses to help our 

 own digestion. In general these digestives should be 

 left to sick people and given under a doctor's direction. 

 Their use easily leads to the habit of depending on 

 them. 



The best aid to digestion is exercise in fresh air. 

 People who live indoors find their digestive troubles 

 disappear as soon as they begin to live an outdoor life. 

 If we neglect exercise too long, digestive troubles be- 

 come chronic. The only safe rule is to set aside a part of 

 every day for exercise. 



The movement of food through the body must not 

 be stopped or clogged. It is very important to avoid 

 constipation. It is easily prevented by eating plenty 

 of fruit and vegetables (as well as bread made of whole 

 wheat or rye), by drinking plenty of water, and by exer- 

 cise of the waist muscles, as in digging, hoeing, or saw- 

 ing wood. 



Those who take plenty of exercise need, as a rule, 

 to pay very little attention to what they eat, but people 

 living largely indoors must eat less, especially of meat, 

 and should in general be careful of their diet. 



Nothing upsets the digestion so quickly as the use of 

 alcoholic drinks. No one should use alcohol during 



