62 



and character of the starch granules due to the treatment received 

 during the process of manufacture. The action of the water, the 

 kneading, rolling, and drying influenced the physical character of the 

 macaroni and possibly caused a slight hydration of the starch and 

 proteids without materially affecting their percentage amounts. 



COMPOSITION OF SAMPLES OF FOOD MATERIALS. 



In connection with the digestion experiments samples of the food 

 materials were analyzed in the usual way (see page 13). In the case 

 of macaroni, samples of the raw material were analyzed. Composite 

 samples of the bread were prepared for analysis in the way described 

 on page 15. For each experimental period a composite sample of the 

 milk or cream, which formed a part of the ration, was prepared by 

 placing in a can each day quantities proportional to the total amounts 

 consumed, potassium })ichromate being used as a preservative. The 

 following table shows the composition of the foods used in the diges- 

 tion experiments: 



Table 44. — Composition of food materials used in digestion experiments with macaroni 



and durum wheat breakfast food. 



COMPOSITION OF FECES AND URINE. 



The urine and feces were collected for analysis in the usual way, the 

 separation of the feces pertaining to each experimental period being 

 secured by the use of lampblack taken in capsules.'* A composite sam- 

 ple of urine was prepared for analyses by uniting aliquot samples of 

 the quantities voided each day. A small amount of formalin was used 

 to prevent fermentation, and the samples were kept in a cool place. 

 Tables 45 and 46 show the composition of the dry matter of the feces 

 and the amount, specific gravity, and nitrogen content of the urine in 

 the digestion experiments. 



«U. S. Dept. Agr., Office of Experiment Stations Bui. 143. 



