181 



Theso difToroncps bctwoon llu' lassos occiirriiifx wlioii meats are 

 cooked with and willioii) eoiitaet with hot water are also jjlaiidy 

 notieeahle w hen the results are calculated to the basis of the \vei»:;ht of 

 the unco()ked meats. The average losses residting in the 1.'^ experi- 

 ments in which the meats were cooked by dry heat thus expressed 

 were: 24.50 per cent water, 0.10 per cent nitrogenous extractives, 

 0.27 per cent nonnitrogenous extractives, 0.43 per cent fat, and 0.13 

 per cent ash. The apparent gain of proteid was 0.70 per cent. 



The average losses resulting in the 31 boiling experiments, expressed 

 in percentages of the weight of the uncooked meats, were 3!). 09 per 

 cent water, 0.63 per cent proteid, 0.S3 per cent nitrogenous extract- 

 ives, 1.07 per cent nonnitrogenous extractives, 1.26 per cent fat, and 

 0.61 per cent ash. 



These conclusions are in accord with those on page 140, drawn from 

 the composition of the cold-water extracts of meat cooked in differ- 

 ent wa3s, that cooking meat by dry heat retains more of the nutri- 

 tive material than cooking it in hot water. 



A STUDY OF MEAT BROTHS AND SOUPS. 



In connection with the nutrition investigations upon meats carried 

 on under the du-ection of this Office" a large amount of luipublished 

 data upon the chemical composition and nutritive value of meats, 

 broths, and soups has been accumulated. Since the available data 

 regarding the composition and true nutritive value of meat broths and 

 soups are as yet quite meager, it has been thought l)est to present this 

 material in connection with this bulletin. Past investigations have 

 shown in a general w^ay that meat broths and soups contain as a rule 

 onl}^ small quantities of true nutritive material, consisting of a por- 

 tion of the nitrogenous and nonnitrogenous organic extractives (meat 

 bases) , proteids, fats, and mineral substances of the meat from which 

 thej^ have been prepared. The true nutritive value of broths is still a 

 disputed question, because a considerable proportion of their solid 

 constituents are composed of the so-called extractives, such as 

 creatin, creatinin, organic acids, glycogen, inosite, and unidentified 

 organic substances and inorganic salts, and the action of these 

 materials upon the animal body is not yet well understood. It seems 

 probable, however, that these extractives have little true nutritive 

 value and that they act cMefly as stimulants to the body or to the 

 process of digestion. 



The extended investigations of Pawlow^ ^ and his associates show 

 that the importance of meat extractives as stimulants to the secretion 

 of normal gastric juice can hardly be overestimated. These bodies 



oU. S. Dept. Agr., Office of Experiment Stations Buls. 102 and 141 

 6 The Work of the Digestive Glands. London, 1902. 



