FOODS AND FOOD HABITS 



55 



but the heat of cooking breaks them, setting free the starch 

 granules which swell and burst under the influence of heat 

 and are thus more thoroughly and easily acted upon by the 

 saliva and other digestive juices; Figs. 23 and 24. Heat 

 acts upon starch much as it does upon grains of corn. We 

 can easily see that popped corn must be more readily digested 

 than unpopped kernels. So far as ease 

 of digestion is concerned the cooking 

 of animal foods is not so important, 

 since the connective tissue which holds 

 the muscle fibres together is easily dis- 

 solved by the digestive juices. Indeed, 

 most meats are more easily digested 

 uncooked, since the proteid in them 

 is coagulated by heat, and must be 

 turned back again to a liquid condition 

 before it can be absorbed. Frying, dur- 

 ing which process the food becomes 

 coated with fat, makes digestion diffi- 

 cult. 



3. There is another entirely sufficient 

 reason for extreme care in the cooking 

 of meats; this is the liability that para- 

 sites of some kind may be present in the FIG 25 _ 

 meat fibres. Such parasites are found TRICHINA. B, A BIT OF 

 more commonly in pork than in any MUSCLE OF PORK 

 other kind of meat generally eaten. An showing trichina between 

 apparently excellent piece of pork may 



contain in a single ounce as many as 85,000 of these little, 

 round worms, trichinae] Fig. 25. If these are swallowed 

 without being killed by thorough cooking, they wander out 

 through the walls of the human food canal and take up 

 their abode in the voluntary muscles of the body. As each 

 female trichina may produce a thousand or more young, it 

 is evident that a serious disease, trichinosis, may result. 



