552 MISCELLANEOUS FARM SUBJECTS 



As regards vegetable foods in general, the consistency and the 

 amounts of solid material were again the principal factors affecting 

 the time required for digestion in the stomach. Mealy potatoes, 

 for instance, were more easily digested than waxy potatoes, and 

 mashed potato more readily than potato cut up in pieces. Fine 

 bread was more quickly digested than coarse bread. There was not 

 much difference in the time required for bread crust, bread crumb, 

 toast, new bread, and stale bread to digest in the stomach, provided 

 all were equally well chewed. (F. B. 249.) 



It must be remembered that digestion continues in the intes- 

 tine and that the total time required for the digestion and absorption 

 of the nutrients in any given food material is not shown by such 

 experiments. They find their chief application in prescribing a 

 diet for invalids, as in such cases it is often desirable to require of 

 the stomach only a limited amount of work. Physicians have used 

 predigested foods of different sorts for their patients for many years. 

 Since the diastase of malt imitates the work of the diastase of saliva 

 and pancreas so well, it is the common means of predigesting carbo- 

 hydrates, when that is necessary, just as the preparations of pepsin 

 and pancreatic juice are used for the predigestion of protein. Or- 

 dinarily predigested foods are intended for invalids under special 

 conditions, and for them only on the doctor's orders. 



About thirty years ago there was a furore over malted fodder 

 for cattle, which it was claimed would greatly increase the strength 

 and flesh of the animals by sparing them part of the work of diges- 

 tion. It was soon found, however, that the cattle did fully as well 

 when left to perform their own work of digestion in the way that 

 nature intended. 



Digestibility is often confused with another very different 

 thing, namely, the agreeing or disagreeing of food with the person 

 who eats it. Different persons are differently constituted with re- 

 spect to the chemical changes which their food undergoes and the 

 effect produced, so that it may be literally true that one man's meat 

 is another man's poison. Milk is for most people a very wholesome, 

 digestible, and nutritious food, but there are persons who are made 

 ill by drinking it. Dr. Atwater mentions a boy who was made se- 

 riously ill by eating eggs. A small piece of sweet cake in which eggs 

 had been used caused him serious trouble. Every person must learn 

 from his or her own experience what food agrees with him or her 

 and what does not. 



In making the experiments noted, the subjects are kept- on a 

 simple diet, all the food and solid excreta are analyzed, and the 

 difference between the two is taken to represent the amount of food 

 which the body secures for nutriment. From comparing the re- 

 sults of many experiments it has been found that in the total food 

 of an ordinary mixed diet, on the average, about 92 per cent of the 

 protein, 95 per cent of the fats, and 97 per cent of the carbohydrates 

 are retained by the body. A slightly greater per cent of these 

 nutrients -are digested in the case of animal food and slightly less 

 in vegetable food, 



