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determine the effect of different methods of cooking meat upon the 

 digestibility of an ordinary mixed diet, including meat, beef being 

 the meat selected. In the remaining 44 experiments the meat was 

 eaten in a very simple diet, the food materials other than meat being 

 those the digestibility of which is fairly well established, so that by 

 making due allowance for these the digestibility of the meat itself 

 may be calculated. Of these, 31 experiments were with beef cooked 

 in water for one, two, and three hours, and by roasting, frying, and 

 pan broiling ; and 6 were with veal, 3 with mutton, and 4 with pork, 

 all roasted. The results of the experiments with beef show the effects 

 of different methods of cooking upon the digestibility of the meat, 

 and a comparison of the results with the various meats cooked in 

 the same way shows the relative digestibility of different kinds of 

 meat. 



In all the experiments with simple diet a study was made of 

 the amounts of metabolic nitrogen in the feces, and in all the 67 

 experiments the urine was collected and the balance of income and 

 outgo of nitrogen was determined. 



In the twenty-three natural digestion experiments with men the 

 same kind of meat beef round cooked in various ways, was eaten 

 with several other common food materials in a rather varied diet. 

 The average digestibility of the nutrients of the total diet was as 

 follows: Protein, 93 per cent; fat, 98 per cent; carbohydrates, 97 

 per cent. These coefficients agree very closely with those found in 

 the average of several hundred digestion experiments with varied 

 diet. 



Differences in method of cooking the meat had no appreciable 

 effect upon the proportions of nutrients digested and absorbed from 

 the total diet. In forty-four experiments different kinds of meat 

 beef, veal, mutton, and pork cooked in various ways, were eaten 

 with two or three other common food materials in a very simple diet, 

 and the digestibility of the meat alone was determined. In the aver- 

 age of the results of these experiments the digestibility of the protein 

 was 98 per cent and of the fat 98 per cent. 



Differences in the results obtained with different kinds of meat 

 or with the same kind of meat cooked in different ways were too 

 small to be of any practical significance. The relative fatness of 

 the meat had no appreciable effect upon the thoroughness of diges- 

 tion, the nutrients of very fat meat being digested as completely as 

 those of very lean meat, including that from which in some cases 

 part of the visible fat had been removed before cooking. In short, 

 all the kinds and cuts of meat were very thoroughly digested, what- 

 ever the method of cooking, and when allowance was made for the 

 metabolic products in the feces, the results obtained indicated that 

 the nutrients of the meat were completely digestible. 



It is commonly said that meats of different sorts vary decidedly 

 in digestibility; for instance, that red meat is less digestible than 

 white meat or beef than pork, or that a cheap cut is less digestible 

 than a tender steak. As regards the thoroughness of digestion the 

 results of the extended series of tests reported show that such differ- 



